[Bug 30980] New: cross compiling with mingw64 is broken

http://bugs.winehq.org/show_bug.cgi?id=30980

Bug #: 30980
           Summary: cross compiling with mingw64 is broken
           Product: Wine
           Version: 1.5.7
          Platform: x86
        OS/Version: Linux
            Status: NEW
          Keywords: download, source
          Severity: normal
          Priority: P2
         Component: build-env
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]
    Classification: Unclassified

Created attachment 40661
  --> http://bugs.winehq.org/attachment.cgi?id=40661
patch

make[1]: Entering directory `/home/austin/wine-git/build-mingw/dlls/crtdll'
i686-w64-mingw32-gcc -c -I../../../wine-cross-temp/dlls/crtdll -I.
-I../../../wine-cross-temp/include -I../../include
-I../../../wine-cross-temp/include/msvcrt -D__WINESRC__  -D_REENTRANT -Wall
-pipe -fno-strength-reduce -fno-strict-aliasing -Wdeclaration-after-statement
-Wempty-body -Wignored-qualifiers -Wstrict-prototypes -Wtype-limits
-Wunused-but-set-parameter -Wwrite-strings -fno-omit-frame-pointer
-Wpointer-arith -Wlogical-op  -g -O2 -D_WIN32 -fno-builtin -o crtdll_main.o
../../../wine-cross-temp/dlls/crtdll/crtdll_main.c
In file included from ../../../wine-cross-temp/include/msvcrt/sys/stat.h:11:0,
                 from ../../../wine-cross-temp/dlls/crtdll/crtdll_main.c:25:
../../../wine-cross-temp/include/msvcrt/crtdefs.h:195:16: error: redefinition
of ���struct localeinfo_struct���
/usr/lib/gcc/i686-w64-mingw32/4.6/../../../../i686-w64-mingw32/include/_mingw.h:649:16:
note: originally defined here
../../../wine-cross-temp/include/msvcrt/crtdefs.h:199:3: error: conflicting
types for ���_locale_tstruct���
/usr/lib/gcc/i686-w64-mingw32/4.6/../../../../i686-w64-mingw32/include/_mingw.h:652:3:
note: previous declaration of ���_locale_tstruct��� was here
../../../wine-cross-temp/include/msvcrt/crtdefs.h:199:21: error: conflicting
types for ���_locale_t���
/usr/lib/gcc/i686-w64-mingw32/4.6/../../../../i686-w64-mingw32/include/_mingw.h:652:20:
note: previous declaration of ���_locale_t��� was here
make[1]: *** [crtdll_main.o] Error 1
make[1]: Leaving directory `/home/austin/wine-git/build-mingw/dlls/crtdll'
make: *** [dlls/crtdll] Error 2

I'll attach a workaround, though I'm not sure if we should prefer mingw or
wine's definition here.