[PATCH v2 0/5] Fix compile errors with MSys2

Git for Windows 2.x is based on MSys2, and its first official version was released already almost half a year ago, yet it is still impossible even to compile Git from the official, platform-independent Git source code.

This patch series merely fixes the compile errors, and will be followed by other patch series that fix the compile warnings and test failures. The idea is to move all Windows-specific patches of Git for Windows' fork to upstream Git proper.

Relative to v1, I only removed the guards about the "#undef ReadWriteBarrier".

Johannes Schindelin (5):
  config.mak.uname: support MSys2
  config.mak.uname: supporting 64-bit MSys2
  nedmalloc: allow compiling with MSys2's compiler
  compat/mingw: support MSys2-based MinGW build
  compat/winansi: support compiling with MSys2

 compat/mingw.h              | 24 +++++++++++++++++++++++-
 compat/nedmalloc/malloc.c.h |  4 ++++
 compat/winansi.c            |  2 ++
 config.mak.uname            | 31 ++++++++++++++++++++++++++++---
 4 files changed, 57 insertions(+), 4 deletions(-)

Interdiff vs v1:

 diff --git a/compat/nedmalloc/malloc.c.h b/compat/nedmalloc/malloc.c.h
 index 18634e3..bf70037 100644
 --- a/compat/nedmalloc/malloc.c.h
 +++ b/compat/nedmalloc/malloc.c.h
 @@ -1385,9 +1385,7 @@ LONG __cdecl _InterlockedExchange(LONG volatile *Target, LONG Value);
  
    /*** Atomic operations ***/
    #if (__GNUC__ * 10000 + __GNUC_MINOR__ * 100 + __GNUC_PATCHLEVEL__) > 40100
 -    #ifdef __MINGW64_VERSION_MAJOR
 -      #undef _ReadWriteBarrier
 -    #endif
 +    #undef _ReadWriteBarrier
      #define _ReadWriteBarrier() __sync_synchronize()
    #else
      static __inline__ __attribute__((always_inline)) long __sync_lock_test_and_set(volatile long * const Target, const long Value)