Define MINGW_W64 and use it instead of _W64

... for detecting MinGW-w64. _W64 is not specific of MinGW-w64, it is
defined for compatibility with MS VC++.

	* nt/inc/ms-w32.h: Define MINGW_W64.

	* admin/CPP-DEFINES: Mention MINGW_W64.

	* nt/addpm.c: Use it.

	* nt/addsection.c: Use it.

	* nt/preprep.c: Use it.

	* src/w32.c: Use MINGW_W64 instead of _W64

	* src/w32term.c: Likewise.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/w32.c b/src/w32.c
index aba0b5a81f9..34f28d01af3 100644
--- a/src/w32.c
+++ b/src/w32.c
@@ -72,8 +72,8 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 #include <pwd.h>
 #include <grp.h>
 
-/* MinGW64 (_W64) defines these in its _mingw.h.  */
-#if defined(__GNUC__) && !defined(_W64)
+/* MinGW64 defines these in its _mingw.h.  */
+#if defined(__GNUC__) && !defined(MINGW_W64)
 #define _ANONYMOUS_UNION
 #define _ANONYMOUS_STRUCT
 #endif
@@ -149,7 +149,7 @@ typedef struct _PROCESS_MEMORY_COUNTERS_EX {
 #define SDDL_REVISION_1 1
 #endif  /* SDDL_REVISION_1 */
 
-#if defined(_MSC_VER) || defined(_W64)
+#if defined(_MSC_VER) || defined(MINGW_W64)
 /* MSVC and MinGW64 don't provide the definition of
    REPARSE_DATA_BUFFER and the associated macros, except on ntifs.h,
    which cannot be included because it triggers conflicts with other