vss-win32: Fix build with mingw64-headers-3.1.0

In mingw64-headers-3.1.0, definition of _com_issue_error() is added, which
conflicts with definition in install.cpp. This adds version checking for
mingw headers to disable the definition when the headers>=3.1 is used.

Signed-off-by: Tomoki Sekiyama <tomoki.sekiyama@hds.com>
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

qga/vss-win32/install.cpp

diff --git a/qga/vss-win32/install.cpp b/qga/vss-win32/install.cpp
index b791a6c..b0e4426 100644
--- a/qga/vss-win32/install.cpp
+++ b/qga/vss-win32/install.cpp
@@ -75,10 +75,13 @@
 
 #define chk(status) _chk(hr, status, "Failed to " #status, out)
 
+#if !defined(__MINGW64_VERSION_MAJOR) || !defined(__MINGW64_VERSION_MINOR) || \
+    __MINGW64_VERSION_MAJOR * 100 + __MINGW64_VERSION_MINOR < 301
 void __stdcall _com_issue_error(HRESULT hr)
 {
     errmsg(hr, "Unexpected error in COM");
 }
+#endif
 
 template<class T>
 HRESULT put_Value(ICatalogObject *pObj, LPCWSTR name, T val)