diff --git a/block-raw-posix.c b/block-raw-posix.c
index 57e3535..8b28a43 100644
--- a/block-raw-posix.c
+++ b/block-raw-posix.c
@@ -750,7 +750,7 @@
     BDRVRawState *s = bs->opaque;
     int fd = s->fd;
     int64_t size;
-#ifdef _BSD
+#ifdef HOST_BSD
     struct stat sb;
 #endif
 #ifdef __sun__
@@ -763,7 +763,7 @@
     if (ret < 0)
         return ret;
 
-#ifdef _BSD
+#ifdef HOST_BSD
     if (!fstat(fd, &sb) && (S_IFCHR & sb.st_mode)) {
 #ifdef DIOCGMEDIASIZE
 	if (ioctl(fd, DIOCGMEDIASIZE, (off_t *)&size))
diff --git a/block.c b/block.c
index 669e021..36de3b6 100644
--- a/block.c
+++ b/block.c
@@ -22,7 +22,7 @@
  * THE SOFTWARE.
  */
 #include "config-host.h"
-#ifdef _BSD
+#ifdef HOST_BSD
 /* include native header before sys-queue.h */
 #include <sys/queue.h>
 #endif
@@ -31,7 +31,7 @@
 #include "monitor.h"
 #include "block_int.h"
 
-#ifdef _BSD
+#ifdef HOST_BSD
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/ioctl.h>
diff --git a/configure b/configure
index a4e6f8d..22795e8 100755
--- a/configure
+++ b/configure
@@ -1520,7 +1520,7 @@
 if [ "$bsd" = "yes" ] ; then
   echo "#define O_LARGEFILE 0" >> $config_h
   echo "#define MAP_ANONYMOUS MAP_ANON" >> $config_h
-  echo "#define _BSD 1" >> $config_h
+  echo "#define HOST_BSD 1" >> $config_h
 fi
 
 echo "#define CONFIG_UNAME_RELEASE \"$uname_release\"" >> $config_h
diff --git a/dyngen-exec.h b/dyngen-exec.h
index 226b114..1fdab65 100644
--- a/dyngen-exec.h
+++ b/dyngen-exec.h
@@ -82,7 +82,7 @@
 #define UINT32_MAX		(4294967295U)
 #define UINT64_MAX		((uint64_t)(18446744073709551615))
 
-#ifdef _BSD
+#ifdef HOST_BSD
 typedef struct __sFILE FILE;
 #else
 typedef struct FILE FILE;
diff --git a/fpu/softfloat-native.c b/fpu/softfloat-native.c
index 90fa8b9..99471b3 100644
--- a/fpu/softfloat-native.c
+++ b/fpu/softfloat-native.c
@@ -6,7 +6,8 @@
 void set_float_rounding_mode(int val STATUS_PARAM)
 {
     STATUS(float_rounding_mode) = val;
-#if defined(_BSD) && !defined(__APPLE__) || (defined(HOST_SOLARIS) && HOST_SOLARIS < 10)
+#if defined(HOST_BSD) && !defined(__APPLE__) ||         \
+    (defined(HOST_SOLARIS) && HOST_SOLARIS < 10)
     fpsetround(val);
 #elif defined(__arm__)
     /* nothing to do */
@@ -22,7 +23,7 @@
 }
 #endif
 
-#if defined(_BSD) || (defined(HOST_SOLARIS) && HOST_SOLARIS < 10)
+#if defined(HOST_BSD) || (defined(HOST_SOLARIS) && HOST_SOLARIS < 10)
 #define lrint(d)		((int32_t)rint(d))
 #define llrint(d)		((int64_t)rint(d))
 #define lrintf(f)		((int32_t)rint(f))
diff --git a/fpu/softfloat-native.h b/fpu/softfloat-native.h
index cf2da4c..6b3a20e 100644
--- a/fpu/softfloat-native.h
+++ b/fpu/softfloat-native.h
@@ -1,7 +1,7 @@
 /* Native implementation of soft float functions */
 #include <math.h>
 
-#if (defined(_BSD) && !defined(__APPLE__)) || defined(HOST_SOLARIS)
+#if (defined(HOST_BSD) && !defined(__APPLE__)) || defined(HOST_SOLARIS)
 #include <ieeefp.h>
 #define fabsf(f) ((float)fabs(f))
 #else
@@ -111,7 +111,7 @@
 /*----------------------------------------------------------------------------
 | Software IEC/IEEE floating-point rounding mode.
 *----------------------------------------------------------------------------*/
-#if (defined(_BSD) && !defined(__APPLE__)) || defined(HOST_SOLARIS)
+#if (defined(HOST_BSD) && !defined(__APPLE__)) || defined(HOST_SOLARIS)
 #if defined(__OpenBSD__)
 #define FE_RM FP_RM
 #define FE_RP FP_RP
diff --git a/net.c b/net.c
index bfd1bd4..90c4b5b 100644
--- a/net.c
+++ b/net.c
@@ -29,7 +29,7 @@
 #include <sys/time.h>
 #include <zlib.h>
 
-/* Needed early for _BSD etc. */
+/* Needed early for HOST_BSD etc. */
 #include "config-host.h"
 
 #ifndef _WIN32
@@ -52,7 +52,7 @@
 #include <dirent.h>
 #include <netdb.h>
 #include <sys/select.h>
-#ifdef _BSD
+#ifdef HOST_BSD
 #include <sys/stat.h>
 #if defined(__FreeBSD__) || defined(__DragonFly__)
 #include <libutil.h>
@@ -769,7 +769,7 @@
     return s;
 }
 
-#if defined (_BSD) || defined (__FreeBSD_kernel__)
+#if defined (HOST_BSD) || defined (__FreeBSD_kernel__)
 static int tap_open(char *ifname, int ifname_size)
 {
     int fd;
diff --git a/osdep.c b/osdep.c
index c34dfd2..a583d77 100644
--- a/osdep.c
+++ b/osdep.c
@@ -33,13 +33,13 @@
 #include <sys/statvfs.h>
 #endif
 
-/* Needed early for _BSD etc. */
+/* Needed early for HOST_BSD etc. */
 #include "config-host.h"
 
 #ifdef _WIN32
 #define WIN32_LEAN_AND_MEAN
 #include <windows.h>
-#elif defined(_BSD)
+#elif defined(HOST_BSD)
 #include <stdlib.h>
 #else
 #include <malloc.h>
@@ -188,7 +188,7 @@
     if (ret != 0)
         return NULL;
     return ptr;
-#elif defined(_BSD)
+#elif defined(HOST_BSD)
     return valloc(size);
 #else
     return memalign(alignment, size);
diff --git a/qemu-char.c b/qemu-char.c
index 566a0ba..c92507b 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -61,7 +61,7 @@
 #include <dirent.h>
 #include <netdb.h>
 #include <sys/select.h>
-#ifdef _BSD
+#ifdef HOST_BSD
 #include <sys/stat.h>
 #ifdef __FreeBSD__
 #include <libutil.h>
diff --git a/savevm.c b/savevm.c
index 8d0ecdc..837a9f0 100644
--- a/savevm.c
+++ b/savevm.c
@@ -29,7 +29,7 @@
 #include <sys/time.h>
 #include <zlib.h>
 
-/* Needed early for _BSD etc. */
+/* Needed early for HOST_BSD etc. */
 #include "config-host.h"
 
 #ifndef _WIN32
@@ -52,7 +52,7 @@
 #include <dirent.h>
 #include <netdb.h>
 #include <sys/select.h>
-#ifdef _BSD
+#ifdef HOST_BSD
 #include <sys/stat.h>
 #if defined(__FreeBSD__) || defined(__DragonFly__)
 #include <libutil.h>
diff --git a/vl.c b/vl.c
index c15f9ac..06e9f73 100644
--- a/vl.c
+++ b/vl.c
@@ -29,7 +29,7 @@
 #include <sys/time.h>
 #include <zlib.h>
 
-/* Needed early for _BSD etc. */
+/* Needed early for HOST_BSD etc. */
 #include "config-host.h"
 
 #ifndef _WIN32
@@ -53,7 +53,7 @@
 #include <dirent.h>
 #include <netdb.h>
 #include <sys/select.h>
-#ifdef _BSD
+#ifdef HOST_BSD
 #include <sys/stat.h>
 #if defined(__FreeBSD__) || defined(__DragonFly__)
 #include <libutil.h>