Fix MinGW64 compilation warnings in w32.c and w32proc.c.

 src/w32proc.c (IsValidLocale) [__GNUC__]: Don't declare prototype,
 since MinGW's w32api headers do.  This avoids compiler warnings.
 src/w32.c (FSCTL_GET_REPARSE_POINT) [_MSC_VER || _W64]: Don't define
 if already defined.

1 files changed, 3 insertions, 0 deletions

diff --git a/src/w32.c b/src/w32.c
index 93a4ce1a8c1..431826c4b82 100644
--- a/src/w32.c
+++ b/src/w32.c
@@ -174,9 +174,12 @@ typedef struct _REPARSE_DATA_BUFFER {
 #ifndef CTL_CODE
 #define CTL_CODE(t,f,m,a)       (((t)<<16)|((a)<<14)|((f)<<2)|(m))
 #endif
+/* MinGW64 defines FSCTL_GET_REPARSE_POINT on winioctl.h.  */
+#ifndef FSCTL_GET_REPARSE_POINT
 #define FSCTL_GET_REPARSE_POINT \
   CTL_CODE(FILE_DEVICE_FILE_SYSTEM, 42, METHOD_BUFFERED, FILE_ANY_ACCESS)
 #endif
+#endif
 
 /* TCP connection support.  */
 #include <sys/socket.h>