I tried to build Mozilla without the cairo stuff: ac_add_options --disable-svg ac_add_options --enable-default-toolkit=windows ac_add_options --disable-canvas I get this build error: _LOGGING=1 -DDETECT_WEBSHELL_LEAKS=1 -DMOZ_TIMELINE=1 -DHAVE___CXA_DEMANGLE=1 -D MOZ_DEMANGLE_SYMBOLS=1 -DMOZ_USER_DIR=\"Mozilla\" -DMOZ_XUL=1 -DMOZ_PROFILELOCKI NG=1 -DMOZ_MORK=1 -DMOZ_DLL_SUFFIX=\".dll\" -DJS_THREADSAFE=1 -DMOZ_REFLOW_PERF= 1 -DMOZ_REFLOW_PERF_DSP=1 -DMOZILLA_LOCALE_VERSION=\"1.9a1\" -DMOZILLA_REGION_VE RSION=\"1.9a1\" -DMOZILLA_SKIN_VERSION=\"1.8\" -D_MOZILLA_CONFIG_H_ -DMOZILLA_C LIENT /cygdrive/c/mozilla/mozilla/widget/src/windows/nsToolkit.cpp c:/mozilla/mozilla/widget/src/windows/nsToolkit.cpp: In function `BOOL CallOpenSaveFileNameA(tagOFNW*, int)': c:/mozilla/mozilla/widget/src/windows/nsToolkit.cpp:423: error: ` OPENFILENAME_SIZE_VERSION_400' undeclared (first use this function) c:/mozilla/mozilla/widget/src/windows/nsToolkit.cpp:423: error: (Each undeclared identifier is reported only once for each function it appears in.) c:/mozilla/mozilla/widget/src/windows/nsToolkit.cpp:508: warning: comparison between signed and unsigned integer expressions c:/mozilla/mozilla/widget/src/windows/nsToolkit.cpp: In static member function `static void MouseTrailer::TimerProc(nsITimer*, void*)': c:/mozilla/mozilla/widget/src/windows/nsToolkit.cpp:1259: warning: passing NULL used for non-pointer argument passing 3 of `BOOL PostMessageA(HWND__*, unsigned int, unsigned int, long int)' c:/mozilla/mozilla/widget/src/windows/nsToolkit.cpp:1259: warning: argument to non-pointer type `unsigned int' from NULL c:/mozilla/mozilla/widget/src/windows/nsToolkit.cpp:1259: warning: passing NULL used for non-pointer argument passing 4 of `BOOL PostMessageA(HWND__*, unsigned int, unsigned int, long int)' c:/mozilla/mozilla/widget/src/windows/nsToolkit.cpp:1259: warning: argument to non-pointer type `long int' from NULL c:/mozilla/mozilla/widget/src/windows/nsToolkit.cpp: In member function `HIMC nsIMM::AssociateContext(HWND__*, long unsigned int)': c:/mozilla/mozilla/widget/src/windows/nsToolkit.cpp:1551: warning: argument to non-pointer type `long unsigned int' from NULL make[6]: *** [nsToolkit.o] Error 1 make[6]: Leaving directory `/cygdrive/c/mozilla/mozilla/widget/src/windows' make[5]: *** [libs] Error 2 make[5]: Leaving directory `/cygdrive/c/mozilla/mozilla/widget/src' make[4]: *** [libs] Error 2 make[4]: Leaving directory `/cygdrive/c/mozilla/mozilla/widget' make[3]: *** [libs_tier_9] Error 2 make[3]: Leaving directory `/cygdrive/c/mozilla/mozilla' make[2]: *** [tier_9] Error 2 make[2]: Leaving directory `/cygdrive/c/mozilla/mozilla' make[1]: *** [alldep] Error 2 make[1]: Leaving directory `/cygdrive/c/mozilla/mozilla' make: *** [alldep] Error 2 I guess this is caused by bug 328306.

This fixes the build issue for me, not sure if it is any good.

Comment on attachment 213569 [details] [diff] [review] patch This will regress bug 328306. If _WIN32_WINNT >= 0x500, mingw header would extend sizeof(OPENFILENAME) while it wouldn't define OPENFILENAME_SIZE_VERSION_400. What about using offsetof(OPENFILENAME, pvReserved)?

According to http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=172797&PageID=1 one can use #define OPENFILENAME_SIZE_VERSION_400 76

Patch as submitted to MinGW, http://sourceforge.net/tracker/index.php?func=detail&aid=1455684&group_id=2435&atid=302435

The patch to MinGW was accepted and is now in the CVS. Please see Bug 328499, Comment 48, for easy update instructions of your w32api headers.