android/build/core/definitions-init.mk - qemu-android - Git at Google

 # Copyright (C) 2009-2010 The Android Open Source Project
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
 #
 #      http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
 #

 # Build system initialization.
 #
 # Input variables:
 #    BUILD_SYSTEM_ROOT
 #       Directory containing the root build system directories, i.e.
 #       'gmsl', 'core', 'awk'.
 #
 #    BUILD_SYSTEM_NAME
 #       Default prefix used in build system logs. Default value is 'Build'.
 #
 #    BUILD_LOG
 #       Set to '1' to enable internal build system logs.
 #
 #    BUILD_SYSTEM_PREBUILT_DIR
 #       If defined, must point to a directory that will contain host
 #       tool binaries under $(BUILD_SYSTEM_PREBUILT_DIR)/<host>/bin/
 #       where <host> can be the 32-bit or 64-bit host tag, depending
 #       on the value of BUILD_FORCE_HOST_32BIT (see below).
 #
 #    BUILD_FORCE_HOST_32BIT
 #       Set to '1' to force the use of 32-bit host prebuilt tool binaries,
 #       when BUILD_SYSTEM_PREBUILT_DIR is defined (ignored otherwise)
 #
 #    BUILD_HOST_OS
 #       Host operating system name. If undefined, will be auto-detected.
 #       Examples: linux, darwin, windows
 #
 #    BUILD_HOST_ARCH
 #       Host operating system architecture. If undefined will be auto-detected.
 #       Examples: x86, x86_64
 #
 #    BUILD_HOST_AWK
 #       Path to the host 'awk' executable. Auto-detected if undefined.
 #
 #    BUILD_HOST_CMP
 #       Path to the host 'cmp' executable. Auto-detected if undefined.
 #
 #    BUILD_HOST_ECHO
 #       Path to the host 'echo' executable. Auto-detected if undefined.
 #
 #    BUILD_HOST_PYTHON
 #       Path to the host 'python' executable. Auto-detected if undefined.

 # Disable GNU Make implicit rules

 # this turns off the suffix rules built into make
 .SUFFIXES:

 # this turns off the RCS / SCCS implicit rules of GNU Make
 % : RCS/%,v
 % : RCS/%
 % : %,v
 % : s.%
 % : SCCS/s.%

 # If a rule fails, delete $@.
 .DELETE_ON_ERROR:

 # ====================================================================
 #
 # Define a few useful variables and functions.
 # More stuff will follow in definitions.mk.
 #
 # ====================================================================

 # Used to output warnings and error from the library, it's possible to
 # disable any warnings or errors by overriding these definitions
 # manually or by setting BUILD_NO_WARNINGS.

 BUILD_SYSTEM_NAME := $(strip $(BUILD_SYSTEM_NAME))
 ifndef BUILD_SYSTEM_NAME
     BUILD_SYSTEM_NAME := Build
 endif

 _build_name    := $(BUILD_SYSTEM_NAME)
 -build-info     = $(info $(_build_name): $1 $2 $3 $4 $5)
 -build-warning  = $(warning $(_build_name): $1 $2 $3 $4 $5)
 -build-error    = $(error $(_build_name): $1 $2 $3 $4 $5)

 ifdef BUILD_NO_WARNINGS
 -build-warning :=
 endif

 # -----------------------------------------------------------------------------
 # Function : -build-log
 # Arguments: 1: text to print when BUILD_LOG is defined to 1
 # Returns  : None
 # Usage    : $(call -build-log,<some text>)
 # -----------------------------------------------------------------------------
 ifeq ($(BUILD_LOG),1)
 _build_log := 1
 -build-log = $(info $(_build_name): $1)
 else
 _build_log := 0
 -build-log :=
 endif

 # Check that we have at least GNU Make 3.81
 # We do this by detecting whether 'lastword' is supported
 #
 MAKE_TEST := $(lastword a b c d e f)
 ifneq ($(MAKE_TEST),f)
     $(call -build-error,GNU Make version $(MAKE_VERSION) is too low (should be >= 3.81))
 endif
 $(call -build-log, GNU Make version $(MAKE_VERSION) detected)


 BUILD_SYSTEM_PREBUILT_DIR := $(strip $(BUILD_SYSTEM_PREBUILT_DIR))
 ifdef BUILD_SYSTEM_PREBUILT_DIR
     ifeq (,$(strip $(wildcard $(BUILD_SYSTEM_PREBUILT_DIR))))
         $(error Missing prebuilts directory: $(BUILD_SYSTEM_PREBUILT_DIR))
     endif
 endif

 # ====================================================================
 #
 # Host system auto-detection.
 #
 # ====================================================================

 #
 # Determine host system and architecture from the environment
 #
 BUILD_HOST_OS := $(strip $(BUILD_HOST_OS))
 ifndef BUILD_HOST_OS
     # On all modern variants of Windows (including Cygwin and Wine)
     # the OS environment variable is defined to 'Windows_NT'
     #
     # The value of PROCESSOR_ARCHITECTURE will be x86 or AMD64
     #
     ifeq ($(OS),Windows_NT)
         BUILD_HOST_OS := windows
     else
         # For other systems, use the `uname` output
         UNAME := $(shell uname -s)
         ifneq (,$(findstring Linux,$(UNAME)))
             BUILD_HOST_OS := linux
         endif
         ifneq (,$(findstring Darwin,$(UNAME)))
             BUILD_HOST_OS := darwin
         endif
         # We should not be there, but just in case !
         ifneq (,$(findstring CYGWIN,$(UNAME)))
             BUILD_HOST_OS := windows
         endif
         ifeq ($(BUILD_HOST_OS),)
             $(call -build-info,Unable to determine BUILD_HOST_OS from uname -s: $(UNAME))
             $(call -build-info,Please define BUILD_HOST_OS in your environment.)
             $(call -build-error,Aborting.)
         endif
     endif
     $(call -build-log,Host OS was auto-detected: $(BUILD_HOST_OS))
 else
     $(call -build-log,Host OS from environment: $(BUILD_HOST_OS))
 endif

 # For all systems, we will have BUILD_HOST_OS_BASE defined as
 # $(BUILD_HOST_OS), except on Cygwin where we will have:
 #
 #  BUILD_HOST_OS      == cygwin
 #  BUILD_HOST_OS_BASE == windows
 #
 # Trying to detect that we're running from Cygwin is tricky
 # because we can't use $(OSTYPE): It's a Bash shell variable
 # that is not exported to sub-processes, and isn't defined by
 # other shells (for those with really weird setups).
 #
 # Instead, we assume that a program named /bin/uname.exe
 # that can be invoked and returns a valid value corresponds
 # to a Cygwin installation.
 #
 BUILD_HOST_OS_BASE := $(BUILD_HOST_OS)

 ifeq ($(BUILD_HOST_OS),windows)
     ifneq (,$(strip $(wildcard /bin/uname.exe)))
         $(call -build-log,Found /bin/uname.exe on Windows host, checking for Cygwin)
         # NOTE: The 2>NUL here is for the case where we're running inside the
         #       native Windows shell. On cygwin, this will create an empty NUL file
         #       that we're going to remove later (see below).
         UNAME := $(shell /bin/uname.exe -s 2>NUL)
         $(call -build-log,uname -s returned: $(UNAME))
         ifneq (,$(filter CYGWIN%,$(UNAME)))
             $(call -build-log,Cygwin detected: $(shell uname -a))
             BUILD_HOST_OS := cygwin
             DUMMY := $(shell rm -f NUL) # Cleaning up
         else
             ifneq (,$(filter MINGW32%,$(UNAME)))
                 $(call -build-log,MSys detected: $(shell uname -a))
                 BUILD_HOST_OS := cygwin
             else
                 $(call -build-log,Cygwin *not* detected!)
             endif
         endif
     endif
 endif

 ifneq ($(BUILD_HOST_OS),$(BUILD_HOST_OS_BASE))
     $(call -build-log, Host operating system detected: $(BUILD_HOST_OS), base OS: $(BUILD_HOST_OS_BASE))
 else
     $(call -build-log, Host operating system detected: $(BUILD_HOST_OS))
 endif

 # Always use /usr/bin/file on Darwin to avoid relying on broken Ports
 # version. See http://b.android.com/53769 .
 BUILD_HOST_FILE_PROGRAM := file
 ifeq ($(BUILD_HOST_OS),darwin)
 BUILD_HOST_FILE_PROGRAM := /usr/bin/file
 endif

 BUILD_HOST_ARCH := $(strip $(BUILD_HOST_ARCH))
 BUILD_HOST_ARCH64 :=
 ifndef BUILD_HOST_ARCH
     ifeq ($(BUILD_HOST_OS_BASE),windows)
         BUILD_HOST_ARCH := $(PROCESSOR_ARCHITECTURE)
         ifeq ($(BUILD_HOST_ARCH),AMD64)
             BUILD_HOST_ARCH := x86
         endif
         # Windows is 64-bit if either ProgramW6432 or ProgramFiles(x86) is set
         ifneq ("/",$(shell echo "%ProgramW6432%/%ProgramFiles(x86)%"))
             BUILD_HOST_ARCH64 := x86_64
         endif
     else # BUILD_HOST_OS_BASE != windows
         UNAME := $(shell uname -m)
         ifneq (,$(findstring 86,$(UNAME)))
             BUILD_HOST_ARCH := x86
             ifneq (,$(shell $(BUILD_HOST_FILE_PROGRAM) -L $(SHELL) | grep 'x86[_-]64'))
                 BUILD_HOST_ARCH64 := x86_64
             endif
         endif
         # We should probably should not care at all
         ifneq (,$(findstring Power,$(UNAME)))
             BUILD_HOST_ARCH := ppc
         endif
         ifeq ($(BUILD_HOST_ARCH),)
             $(call -build-info,Unsupported host architecture: $(UNAME))
             $(call -build-error,Aborting)
         endif
     endif # BUILD_HOST_OS_BASE != windows
     $(call -build-log,Host CPU was auto-detected: $(BUILD_HOST_ARCH))
 else
     $(call -build-log,Host CPU from environment: $(BUILD_HOST_ARCH))
 endif

 ifeq (,$(BUILD_HOST_ARCH64))
     BUILD_HOST_ARCH64 := $(BUILD_HOST_ARCH)
 endif

 BUILD_HOST_TAG := $(BUILD_HOST_OS_BASE)-$(BUILD_HOST_ARCH)
 BUILD_HOST_TAG64 := $(BUILD_HOST_OS_BASE)-$(BUILD_HOST_ARCH64)

 # The directory separator used on this host
 BUILD_HOST_DIRSEP := :
 ifeq ($(BUILD_HOST_OS),windows)
   BUILD_HOST_DIRSEP := ;
 endif

 # The host executable extension
 BUILD_HOST_EXEEXT :=
 ifeq ($(BUILD_HOST_OS),windows)
   BUILD_HOST_EXEEXT := .exe
 endif

 # If we are on Windows, we need to check that we are not running
 # Cygwin 1.5, which is deprecated and won't run our toolchain
 # binaries properly.
 #
 ifeq ($(BUILD_HOST_TAG),windows-x86)
     ifeq ($(BUILD_HOST_OS),cygwin)
         # On cygwin, 'uname -r' returns something like 1.5.23(0.225/5/3)
         # We recognize 1.5. as the prefix to look for then.
         CYGWIN_VERSION := $(shell uname -r)
         ifneq ($(filter XX1.5.%,XX$(CYGWIN_VERSION)),)
             $(call -build-info,You seem to be running Cygwin 1.5, which is not supported.)
             $(call -build-info,Please upgrade to Cygwin 1.7 or higher.)
             $(call -build-error,Aborting.)
         endif
     endif
     # special-case the host-tag
     BUILD_HOST_TAG := windows
 endif

 $(call -build-log,BUILD_HOST_TAG set to $(BUILD_HOST_TAG))

 # Check for build-system-specific versions of our host tools
 ifneq (,$(BUILD_SYSTEM_PREBUILT_DIR))
     ifeq (1,$(BUILD_FORCE_HOST_32BIT))
         BUILD_HOST_PREBUILT_DIR := $(BUILD_SYSTEM_PREBUILT_DIR)/$(BUILD_HOST_TAG)
     else
         BUILD_HOST_PREBUILT_DIR := $(BUILD_SYSTEM_PREBUILT_DIR)/$(BUILD_HOST_TAG64)
         ifeq (,$(strip $(wildcard $(BUILD_HOST_PREBUILT_DIR))))
             BUILD_HOST_PREBUILT_DIR := $(BUILD_SYSTEM_PREBUILT_DIR)/$(BUILD_HOST_TAG)
         endif
     endif
     BUILD_HOST_PREBUILT_DIR := $(strip $(wildcard $(BUILD_HOST_PREBUILT_DIR)))
 else
     BUILD_HOST_PREBUILT_DIR :=
 endif

 BUILD_HOST_AWK := $(strip $(BUILD_HOST_AWK))
 BUILD_HOST_PYTHON := $(strip $(BUILD_HOST_PYTHON))

 ifdef BUILD_HOST_PREBUILT_DIR
     $(call -build-log,Host tools prebuilt directory: $(BUILD_HOST_PREBUILT_DIR))
     # The windows prebuilt binaries are for ndk-build.cmd
     # On cygwin, we must use the Cygwin version of these tools instead.
     ifneq ($(BUILD_HOST_OS),cygwin)
         ifndef BUILD_HOST_AWK
             BUILD_HOST_AWK := $(wildcard $(BUILD_HOST_PREBUILT_DIR)/awk$(BUILD_HOST_EXEEXT))
         endif
         ifndef BUILD_HOST_PYTHON
             BUILD_HOST_PYTHON := $(wildcard $(BUILD_HOST_PREBUILT_DIR)/python$(BUILD_HOST_EXEEXT))
         endif
     endif
 else
     $(call -build-log,Host tools prebuilt directory not found, using system tools)
 endif

 BUILD_HOST_ECHO := $(strip $(BUILD_HOST_ECHO))
 ifdef BUILD_HOST_PREBUILT_DIR
     ifndef BUILD_HOST_ECHO
         # Special case, on Cygwin, always use the host echo, not our prebuilt one
         # which adds \r\n at the end of lines.
         ifneq ($(BUILD_HOST_OS),cygwin)
             BUILD_HOST_ECHO := $(strip $(wildcard $(BUILD_HOST_PREBUILT_DIR)/echo$(BUILD_HOST_EXEEXT)))
         endif
     endif
 endif
 ifndef BUILD_HOST_ECHO
     BUILD_HOST_ECHO := echo
 endif
 $(call -build-log,Host 'echo' tool: $(BUILD_HOST_ECHO))

 # Define BUILD_HOST_ECHO_N to perform the equivalent of 'echo -n' on all platforms.
 ifeq ($(BUILD_HOST_OS),windows)
   # Our custom toolbox echo binary supports -n.
   BUILD_HOST_ECHO_N := $(BUILD_HOST_ECHO) -n
 else
   # On Posix, just use bare printf.
   BUILD_HOST_ECHO_N := printf %s
 endif
 $(call -build-log,Host 'echo -n' tool: $(BUILD_HOST_ECHO_N))

 BUILD_HOST_CMP := $(strip $(BUILD_HOST_CMP))
 ifdef BUILD_HOST_PREBUILT_DIR
     ifndef BUILD_HOST_CMP
         BUILD_HOST_CMP := $(strip $(wildcard $(BUILD_HOST_PREBUILT_DIR)/cmp$(BUILD_HOST_EXEEXT)))
     endif
 endif
 ifndef BUILD_HOST_CMP
     BUILD_HOST_CMP := cmp
 endif
 $(call -build-log,Host 'cmp' tool: $(BUILD_HOST_CMP))

 #
 # Verify that the 'awk' tool has the features we need.
 # Both Nawk and Gawk do.
 #
 BUILD_HOST_AWK := $(strip $(BUILD_HOST_AWK))
 ifndef BUILD_HOST_AWK
     BUILD_HOST_AWK := awk
 endif
 $(call -build-log,Host 'awk' tool: $(BUILD_HOST_AWK))

 # Location of all awk scripts we use
 BUILD_AWK := $(BUILD_SYSTEM_ROOT)/awk
 ifeq (,$(strip $(wildcard $(BUILD_AWK))))
     $(call -build-error,Missing awk scripts directory: $(BUILD_AWK))
 endif

 AWK_TEST := $(shell $(BUILD_HOST_AWK) -f $(BUILD_AWK)/check-awk.awk)
 $(call -build-log,Host 'awk' test returned: $(AWK_TEST))
 ifneq ($(AWK_TEST),Pass)
     $(call -build-info,Host 'awk' tool is outdated. Please define BUILD_HOST_AWK to point to Gawk or Nawk !)
     $(call -build-error,Aborting.)
 endif

 #
 # On Cygwin/MSys, define the 'cygwin-to-host-path' function here depending on the
 # environment. The rules are the following:
 #
 # 1/ If BUILD_USE_CYGPATH=1 and cygpath does exist in your path, cygwin-to-host-path
 #    calls "cygpath -m" for each host path.  Since invoking 'cygpath -m' from GNU
 #    Make for each source file is _very_ slow, this is only a backup plan in
 #    case our automatic substitution function (described below) doesn't work.
 #
 # 2/ Generate a Make function that performs the mapping from cygwin/msys to host
 #    paths through simple substitutions.  It's really a series of nested patsubst
 #    calls, that loo like:
 #
 #     cygwin-to-host-path = $(patsubst /cygdrive/c/%,c:/%,\
 #                             $(patsusbt /cygdrive/d/%,d:/%, \
 #                              $1)
 #    or in MSys:
 #     cygwin-to-host-path = $(patsubst /c/%,c:/%,\
 #                             $(patsusbt /d/%,d:/%, \
 #                              $1)
 #
 # except that the actual definition is built from the list of mounted
 # drives as reported by "mount" and deals with drive letter cases (i.e.
 # '/cygdrive/c' and '/cygdrive/C')
 #
 ifeq ($(BUILD_HOST_OS),cygwin)
     CYGPATH := $(strip $(HOST_CYGPATH))
     ifndef CYGPATH
         $(call -build-log, Probing for 'cygpath' program)
         CYGPATH := $(strip $(shell which cygpath 2>/dev/null))
         ifndef CYGPATH
             $(call -build-log, 'cygpath' was *not* found in your path)
         else
             $(call -build-log, 'cygpath' found as: $(CYGPATH))
         endif
     endif

     ifeq ($(BUILD_USE_CYGPATH),1)
         ifndef CYGPATH
             $(call -build-info,No cygpath)
             $(call -build-error,Aborting)
         endif
         $(call -build-log, Forced usage of 'cygpath -m' through BUILD_USE_CYGPATH=1)
         cygwin-to-host-path = $(strip $(shell $(CYGPATH) -m $1))
     else
         # Call an awk script to generate a Makefile fragment used to define a function
         WINDOWS_HOST_PATH_FRAGMENT := $(shell mount | tr '\\' '/' | $(BUILD_HOST_AWK) -f $(BUILD_AWK)/gen-windows-host-path.awk)
         ifeq ($(_build_log),1)
             $(info Using cygwin substitution rules:)
             $(eval $(shell mount | tr '\\' '/' | $(BUILD_HOST_AWK) -f $(BUILD_AWK)/gen-windows-host-path.awk -vVERBOSE=1))
         endif
         $(eval cygwin-to-host-path = $(WINDOWS_HOST_PATH_FRAGMENT))
     endif
 endif # BUILD_HOST_OS == cygwin

 # -----------------------------------------------------------------------------
 # Function : host-prebuilt-tag
 # Arguments: 1: parent path of "prebuilt"
 # Returns  : path $1/prebuilt/(BUILD_HOST_TAG64) exists and BUILD_FORCE_HOST_32BIT
 #            isn't defined to 1, or $1/prebuilt/(BUILD_HOST_TAG)
 # Usage    : $(call host-prebuilt-tag, <path>)
 # Rationale: This function is used to proble available 64-bit toolchain or
 #            return 32-bit one as default.  Note that BUILD_HOST_TAG64==BUILD_HOST_TAG for
 #            32-bit system (or 32-bit userland in 64-bit system)
 # -----------------------------------------------------------------------------
 ifeq ($(BUILD_FORCE_HOST_32BIT),1)
 host-prebuilt-tag = $1/prebuilt/$(BUILD_HOST_TAG)
 else
 host-prebuilt-tag = $(strip \
     $(if $(strip $(wildcard $1/prebuilt/$(BUILD_HOST_TAG64))),\
         $1/prebuilt/$(BUILD_HOST_TAG64),\
         $1/prebuilt/$(BUILD_HOST_TAG)\
     ))
 endif
	# Copyright (C) 2009-2010 The Android Open Source Project
	#
	# Licensed under the Apache License, Version 2.0 (the "License");
	# you may not use this file except in compliance with the License.
	# You may obtain a copy of the License at
	#
	# http://www.apache.org/licenses/LICENSE-2.0
	#
	# Unless required by applicable law or agreed to in writing, software
	# distributed under the License is distributed on an "AS IS" BASIS,
	# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	# See the License for the specific language governing permissions and
	# limitations under the License.
	#

	# Build system initialization.
	#
	# Input variables:
	# BUILD_SYSTEM_ROOT
	# Directory containing the root build system directories, i.e.
	# 'gmsl', 'core', 'awk'.
	#
	# BUILD_SYSTEM_NAME
	# Default prefix used in build system logs. Default value is 'Build'.
	#
	# BUILD_LOG
	# Set to '1' to enable internal build system logs.
	#
	# BUILD_SYSTEM_PREBUILT_DIR
	# If defined, must point to a directory that will contain host
	# tool binaries under $(BUILD_SYSTEM_PREBUILT_DIR)/<host>/bin/
	# where <host> can be the 32-bit or 64-bit host tag, depending
	# on the value of BUILD_FORCE_HOST_32BIT (see below).
	#
	# BUILD_FORCE_HOST_32BIT
	# Set to '1' to force the use of 32-bit host prebuilt tool binaries,
	# when BUILD_SYSTEM_PREBUILT_DIR is defined (ignored otherwise)
	#
	# BUILD_HOST_OS
	# Host operating system name. If undefined, will be auto-detected.
	# Examples: linux, darwin, windows
	#
	# BUILD_HOST_ARCH
	# Host operating system architecture. If undefined will be auto-detected.
	# Examples: x86, x86_64
	#
	# BUILD_HOST_AWK
	# Path to the host 'awk' executable. Auto-detected if undefined.
	#
	# BUILD_HOST_CMP
	# Path to the host 'cmp' executable. Auto-detected if undefined.
	#
	# BUILD_HOST_ECHO
	# Path to the host 'echo' executable. Auto-detected if undefined.
	#
	# BUILD_HOST_PYTHON
	# Path to the host 'python' executable. Auto-detected if undefined.

	# Disable GNU Make implicit rules

	# this turns off the suffix rules built into make
	.SUFFIXES:

	# this turns off the RCS / SCCS implicit rules of GNU Make
	% : RCS/%,v
	% : RCS/%
	% : %,v
	% : s.%
	% : SCCS/s.%

	# If a rule fails, delete $@.
	.DELETE_ON_ERROR:

	# ====================================================================
	#
	# Define a few useful variables and functions.
	# More stuff will follow in definitions.mk.
	#
	# ====================================================================

	# Used to output warnings and error from the library, it's possible to
	# disable any warnings or errors by overriding these definitions
	# manually or by setting BUILD_NO_WARNINGS.

	BUILD_SYSTEM_NAME := $(strip $(BUILD_SYSTEM_NAME))
	ifndef BUILD_SYSTEM_NAME
	BUILD_SYSTEM_NAME := Build
	endif

	_build_name := $(BUILD_SYSTEM_NAME)
	-build-info = $(info $(_build_name): $1 $2 $3 $4 $5)
	-build-warning = $(warning $(_build_name): $1 $2 $3 $4 $5)
	-build-error = $(error $(_build_name): $1 $2 $3 $4 $5)

	ifdef BUILD_NO_WARNINGS
	-build-warning :=
	endif

	# -----------------------------------------------------------------------------
	# Function : -build-log
	# Arguments: 1: text to print when BUILD_LOG is defined to 1
	# Returns : None
	# Usage : $(call -build-log,<some text>)
	# -----------------------------------------------------------------------------
	ifeq ($(BUILD_LOG),1)
	_build_log := 1
	-build-log = $(info $(_build_name): $1)
	else
	_build_log := 0
	-build-log :=
	endif

	# Check that we have at least GNU Make 3.81
	# We do this by detecting whether 'lastword' is supported
	#
	MAKE_TEST := $(lastword a b c d e f)
	ifneq ($(MAKE_TEST),f)
	$(call -build-error,GNU Make version $(MAKE_VERSION) is too low (should be >= 3.81))
	endif
	$(call -build-log, GNU Make version $(MAKE_VERSION) detected)


	BUILD_SYSTEM_PREBUILT_DIR := $(strip $(BUILD_SYSTEM_PREBUILT_DIR))
	ifdef BUILD_SYSTEM_PREBUILT_DIR
	ifeq (,$(strip $(wildcard $(BUILD_SYSTEM_PREBUILT_DIR))))
	$(error Missing prebuilts directory: $(BUILD_SYSTEM_PREBUILT_DIR))
	endif
	endif

	# ====================================================================
	#
	# Host system auto-detection.
	#
	# ====================================================================

	#
	# Determine host system and architecture from the environment
	#
	BUILD_HOST_OS := $(strip $(BUILD_HOST_OS))
	ifndef BUILD_HOST_OS
	# On all modern variants of Windows (including Cygwin and Wine)
	# the OS environment variable is defined to 'Windows_NT'
	#
	# The value of PROCESSOR_ARCHITECTURE will be x86 or AMD64
	#
	ifeq ($(OS),Windows_NT)
	BUILD_HOST_OS := windows
	else
	# For other systems, use the `uname` output
	UNAME := $(shell uname -s)
	ifneq (,$(findstring Linux,$(UNAME)))
	BUILD_HOST_OS := linux
	endif
	ifneq (,$(findstring Darwin,$(UNAME)))
	BUILD_HOST_OS := darwin
	endif
	# We should not be there, but just in case !
	ifneq (,$(findstring CYGWIN,$(UNAME)))
	BUILD_HOST_OS := windows
	endif
	ifeq ($(BUILD_HOST_OS),)
	$(call -build-info,Unable to determine BUILD_HOST_OS from uname -s: $(UNAME))
	$(call -build-info,Please define BUILD_HOST_OS in your environment.)
	$(call -build-error,Aborting.)
	endif
	endif
	$(call -build-log,Host OS was auto-detected: $(BUILD_HOST_OS))
	else
	$(call -build-log,Host OS from environment: $(BUILD_HOST_OS))
	endif

	# For all systems, we will have BUILD_HOST_OS_BASE defined as
	# $(BUILD_HOST_OS), except on Cygwin where we will have:
	#
	# BUILD_HOST_OS == cygwin
	# BUILD_HOST_OS_BASE == windows
	#
	# Trying to detect that we're running from Cygwin is tricky
	# because we can't use $(OSTYPE): It's a Bash shell variable
	# that is not exported to sub-processes, and isn't defined by
	# other shells (for those with really weird setups).
	#
	# Instead, we assume that a program named /bin/uname.exe
	# that can be invoked and returns a valid value corresponds
	# to a Cygwin installation.
	#
	BUILD_HOST_OS_BASE := $(BUILD_HOST_OS)

	ifeq ($(BUILD_HOST_OS),windows)
	ifneq (,$(strip $(wildcard /bin/uname.exe)))
	$(call -build-log,Found /bin/uname.exe on Windows host, checking for Cygwin)
	# NOTE: The 2>NUL here is for the case where we're running inside the
	# native Windows shell. On cygwin, this will create an empty NUL file
	# that we're going to remove later (see below).
	UNAME := $(shell /bin/uname.exe -s 2>NUL)
	$(call -build-log,uname -s returned: $(UNAME))
	ifneq (,$(filter CYGWIN%,$(UNAME)))
	$(call -build-log,Cygwin detected: $(shell uname -a))
	BUILD_HOST_OS := cygwin
	DUMMY := $(shell rm -f NUL) # Cleaning up
	else
	ifneq (,$(filter MINGW32%,$(UNAME)))
	$(call -build-log,MSys detected: $(shell uname -a))
	BUILD_HOST_OS := cygwin
	else
	$(call -build-log,Cygwin not detected!)
	endif
	endif
	endif
	endif

	ifneq ($(BUILD_HOST_OS),$(BUILD_HOST_OS_BASE))
	$(call -build-log, Host operating system detected: $(BUILD_HOST_OS), base OS: $(BUILD_HOST_OS_BASE))
	else
	$(call -build-log, Host operating system detected: $(BUILD_HOST_OS))
	endif

	# Always use /usr/bin/file on Darwin to avoid relying on broken Ports
	# version. See http://b.android.com/53769 .
	BUILD_HOST_FILE_PROGRAM := file
	ifeq ($(BUILD_HOST_OS),darwin)
	BUILD_HOST_FILE_PROGRAM := /usr/bin/file
	endif

	BUILD_HOST_ARCH := $(strip $(BUILD_HOST_ARCH))
	BUILD_HOST_ARCH64 :=
	ifndef BUILD_HOST_ARCH
	ifeq ($(BUILD_HOST_OS_BASE),windows)
	BUILD_HOST_ARCH := $(PROCESSOR_ARCHITECTURE)
	ifeq ($(BUILD_HOST_ARCH),AMD64)
	BUILD_HOST_ARCH := x86
	endif
	# Windows is 64-bit if either ProgramW6432 or ProgramFiles(x86) is set
	ifneq ("/",$(shell echo "%ProgramW6432%/%ProgramFiles(x86)%"))
	BUILD_HOST_ARCH64 := x86_64
	endif
	else # BUILD_HOST_OS_BASE != windows
	UNAME := $(shell uname -m)
	ifneq (,$(findstring 86,$(UNAME)))
	BUILD_HOST_ARCH := x86
	ifneq (,$(shell $(BUILD_HOST_FILE_PROGRAM) -L $(SHELL) \| grep 'x86[_-]64'))
	BUILD_HOST_ARCH64 := x86_64
	endif
	endif
	# We should probably should not care at all
	ifneq (,$(findstring Power,$(UNAME)))
	BUILD_HOST_ARCH := ppc
	endif
	ifeq ($(BUILD_HOST_ARCH),)
	$(call -build-info,Unsupported host architecture: $(UNAME))
	$(call -build-error,Aborting)
	endif
	endif # BUILD_HOST_OS_BASE != windows
	$(call -build-log,Host CPU was auto-detected: $(BUILD_HOST_ARCH))
	else
	$(call -build-log,Host CPU from environment: $(BUILD_HOST_ARCH))
	endif

	ifeq (,$(BUILD_HOST_ARCH64))
	BUILD_HOST_ARCH64 := $(BUILD_HOST_ARCH)
	endif

	BUILD_HOST_TAG := $(BUILD_HOST_OS_BASE)-$(BUILD_HOST_ARCH)
	BUILD_HOST_TAG64 := $(BUILD_HOST_OS_BASE)-$(BUILD_HOST_ARCH64)

	# The directory separator used on this host
	BUILD_HOST_DIRSEP := :
	ifeq ($(BUILD_HOST_OS),windows)
	BUILD_HOST_DIRSEP := ;
	endif

	# The host executable extension
	BUILD_HOST_EXEEXT :=
	ifeq ($(BUILD_HOST_OS),windows)
	BUILD_HOST_EXEEXT := .exe
	endif

	# If we are on Windows, we need to check that we are not running
	# Cygwin 1.5, which is deprecated and won't run our toolchain
	# binaries properly.
	#
	ifeq ($(BUILD_HOST_TAG),windows-x86)
	ifeq ($(BUILD_HOST_OS),cygwin)
	# On cygwin, 'uname -r' returns something like 1.5.23(0.225/5/3)
	# We recognize 1.5. as the prefix to look for then.
	CYGWIN_VERSION := $(shell uname -r)
	ifneq ($(filter XX1.5.%,XX$(CYGWIN_VERSION)),)
	$(call -build-info,You seem to be running Cygwin 1.5, which is not supported.)
	$(call -build-info,Please upgrade to Cygwin 1.7 or higher.)
	$(call -build-error,Aborting.)
	endif
	endif
	# special-case the host-tag
	BUILD_HOST_TAG := windows
	endif

	$(call -build-log,BUILD_HOST_TAG set to $(BUILD_HOST_TAG))

	# Check for build-system-specific versions of our host tools
	ifneq (,$(BUILD_SYSTEM_PREBUILT_DIR))
	ifeq (1,$(BUILD_FORCE_HOST_32BIT))
	BUILD_HOST_PREBUILT_DIR := $(BUILD_SYSTEM_PREBUILT_DIR)/$(BUILD_HOST_TAG)
	else
	BUILD_HOST_PREBUILT_DIR := $(BUILD_SYSTEM_PREBUILT_DIR)/$(BUILD_HOST_TAG64)
	ifeq (,$(strip $(wildcard $(BUILD_HOST_PREBUILT_DIR))))
	BUILD_HOST_PREBUILT_DIR := $(BUILD_SYSTEM_PREBUILT_DIR)/$(BUILD_HOST_TAG)
	endif
	endif
	BUILD_HOST_PREBUILT_DIR := $(strip $(wildcard $(BUILD_HOST_PREBUILT_DIR)))
	else
	BUILD_HOST_PREBUILT_DIR :=
	endif

	BUILD_HOST_AWK := $(strip $(BUILD_HOST_AWK))
	BUILD_HOST_PYTHON := $(strip $(BUILD_HOST_PYTHON))

	ifdef BUILD_HOST_PREBUILT_DIR
	$(call -build-log,Host tools prebuilt directory: $(BUILD_HOST_PREBUILT_DIR))
	# The windows prebuilt binaries are for ndk-build.cmd
	# On cygwin, we must use the Cygwin version of these tools instead.
	ifneq ($(BUILD_HOST_OS),cygwin)
	ifndef BUILD_HOST_AWK
	BUILD_HOST_AWK := $(wildcard $(BUILD_HOST_PREBUILT_DIR)/awk$(BUILD_HOST_EXEEXT))
	endif
	ifndef BUILD_HOST_PYTHON
	BUILD_HOST_PYTHON := $(wildcard $(BUILD_HOST_PREBUILT_DIR)/python$(BUILD_HOST_EXEEXT))
	endif
	endif
	else
	$(call -build-log,Host tools prebuilt directory not found, using system tools)
	endif

	BUILD_HOST_ECHO := $(strip $(BUILD_HOST_ECHO))
	ifdef BUILD_HOST_PREBUILT_DIR
	ifndef BUILD_HOST_ECHO
	# Special case, on Cygwin, always use the host echo, not our prebuilt one
	# which adds \r\n at the end of lines.
	ifneq ($(BUILD_HOST_OS),cygwin)
	BUILD_HOST_ECHO := $(strip $(wildcard $(BUILD_HOST_PREBUILT_DIR)/echo$(BUILD_HOST_EXEEXT)))
	endif
	endif
	endif
	ifndef BUILD_HOST_ECHO
	BUILD_HOST_ECHO := echo
	endif
	$(call -build-log,Host 'echo' tool: $(BUILD_HOST_ECHO))

	# Define BUILD_HOST_ECHO_N to perform the equivalent of 'echo -n' on all platforms.
	ifeq ($(BUILD_HOST_OS),windows)
	# Our custom toolbox echo binary supports -n.
	BUILD_HOST_ECHO_N := $(BUILD_HOST_ECHO) -n
	else
	# On Posix, just use bare printf.
	BUILD_HOST_ECHO_N := printf %s
	endif
	$(call -build-log,Host 'echo -n' tool: $(BUILD_HOST_ECHO_N))

	BUILD_HOST_CMP := $(strip $(BUILD_HOST_CMP))
	ifdef BUILD_HOST_PREBUILT_DIR
	ifndef BUILD_HOST_CMP
	BUILD_HOST_CMP := $(strip $(wildcard $(BUILD_HOST_PREBUILT_DIR)/cmp$(BUILD_HOST_EXEEXT)))
	endif
	endif
	ifndef BUILD_HOST_CMP
	BUILD_HOST_CMP := cmp
	endif
	$(call -build-log,Host 'cmp' tool: $(BUILD_HOST_CMP))

	#
	# Verify that the 'awk' tool has the features we need.
	# Both Nawk and Gawk do.
	#
	BUILD_HOST_AWK := $(strip $(BUILD_HOST_AWK))
	ifndef BUILD_HOST_AWK
	BUILD_HOST_AWK := awk
	endif
	$(call -build-log,Host 'awk' tool: $(BUILD_HOST_AWK))

	# Location of all awk scripts we use
	BUILD_AWK := $(BUILD_SYSTEM_ROOT)/awk
	ifeq (,$(strip $(wildcard $(BUILD_AWK))))
	$(call -build-error,Missing awk scripts directory: $(BUILD_AWK))
	endif

	AWK_TEST := $(shell $(BUILD_HOST_AWK) -f $(BUILD_AWK)/check-awk.awk)
	$(call -build-log,Host 'awk' test returned: $(AWK_TEST))
	ifneq ($(AWK_TEST),Pass)
	$(call -build-info,Host 'awk' tool is outdated. Please define BUILD_HOST_AWK to point to Gawk or Nawk !)
	$(call -build-error,Aborting.)
	endif

	#
	# On Cygwin/MSys, define the 'cygwin-to-host-path' function here depending on the
	# environment. The rules are the following:
	#
	# 1/ If BUILD_USE_CYGPATH=1 and cygpath does exist in your path, cygwin-to-host-path
	# calls "cygpath -m" for each host path. Since invoking 'cygpath -m' from GNU
	# Make for each source file is _very_ slow, this is only a backup plan in
	# case our automatic substitution function (described below) doesn't work.
	#
	# 2/ Generate a Make function that performs the mapping from cygwin/msys to host
	# paths through simple substitutions. It's really a series of nested patsubst
	# calls, that loo like:
	#
	# cygwin-to-host-path = $(patsubst /cygdrive/c/%,c:/%,\
	# $(patsusbt /cygdrive/d/%,d:/%, \
	# $1)
	# or in MSys:
	# cygwin-to-host-path = $(patsubst /c/%,c:/%,\
	# $(patsusbt /d/%,d:/%, \
	# $1)
	#
	# except that the actual definition is built from the list of mounted
	# drives as reported by "mount" and deals with drive letter cases (i.e.
	# '/cygdrive/c' and '/cygdrive/C')
	#
	ifeq ($(BUILD_HOST_OS),cygwin)
	CYGPATH := $(strip $(HOST_CYGPATH))
	ifndef CYGPATH
	$(call -build-log, Probing for 'cygpath' program)
	CYGPATH := $(strip $(shell which cygpath 2>/dev/null))
	ifndef CYGPATH
	$(call -build-log, 'cygpath' was not found in your path)
	else
	$(call -build-log, 'cygpath' found as: $(CYGPATH))
	endif
	endif

	ifeq ($(BUILD_USE_CYGPATH),1)
	ifndef CYGPATH
	$(call -build-info,No cygpath)
	$(call -build-error,Aborting)
	endif
	$(call -build-log, Forced usage of 'cygpath -m' through BUILD_USE_CYGPATH=1)
	cygwin-to-host-path = $(strip $(shell $(CYGPATH) -m $1))
	else
	# Call an awk script to generate a Makefile fragment used to define a function
	WINDOWS_HOST_PATH_FRAGMENT := $(shell mount \| tr '\\' '/' \| $(BUILD_HOST_AWK) -f $(BUILD_AWK)/gen-windows-host-path.awk)
	ifeq ($(_build_log),1)
	$(info Using cygwin substitution rules:)
	$(eval $(shell mount \| tr '\\' '/' \| $(BUILD_HOST_AWK) -f $(BUILD_AWK)/gen-windows-host-path.awk -vVERBOSE=1))
	endif
	$(eval cygwin-to-host-path = $(WINDOWS_HOST_PATH_FRAGMENT))
	endif
	endif # BUILD_HOST_OS == cygwin

	# -----------------------------------------------------------------------------
	# Function : host-prebuilt-tag
	# Arguments: 1: parent path of "prebuilt"
	# Returns : path $1/prebuilt/(BUILD_HOST_TAG64) exists and BUILD_FORCE_HOST_32BIT
	# isn't defined to 1, or $1/prebuilt/(BUILD_HOST_TAG)
	# Usage : $(call host-prebuilt-tag, <path>)
	# Rationale: This function is used to proble available 64-bit toolchain or
	# return 32-bit one as default. Note that BUILD_HOST_TAG64==BUILD_HOST_TAG for
	# 32-bit system (or 32-bit userland in 64-bit system)
	# -----------------------------------------------------------------------------
	ifeq ($(BUILD_FORCE_HOST_32BIT),1)
	host-prebuilt-tag = $1/prebuilt/$(BUILD_HOST_TAG)
	else
	host-prebuilt-tag = $(strip \
	$(if $(strip $(wildcard $1/prebuilt/$(BUILD_HOST_TAG64))),\
	$1/prebuilt/$(BUILD_HOST_TAG64),\
	$1/prebuilt/$(BUILD_HOST_TAG)\
	))
	endif