Fix incompatibilities between MinGW.org and MinGW64 headers

Problems were reported by ׃scar Fuentes in
 
  http://lists.gnu.org/archive/html/emacs-devel/2013-03/msg00611.html.

 nt/inc/ms-w32.h (struct timespec): Don't define if
 _TIMESPEC_DEFINED is already defined.
 (sigset_t) [!_POSIX]: Typedef for MinGW64.
 (_WIN32_WINNT, WIN32_LEAN_AND_MEAN): Move definitions before
 including the first system header, to avoid redefinition if some
 system header defines a default value.
 nt/inc/sys/time.h (struct itimerval): Don't define if
 _TIMESPEC_DEFINED is already defined.

nt/ChangeLog

+2013-03-25  Eli Zaretskii  <eliz@gnu.org>
+
+	Fix incompatibilities between MinGW.org and MinGW64 headers
+	reported by Óscar Fuentes in
+	http://lists.gnu.org/archive/html/emacs-devel/2013-03/msg00611.html.
+	* inc/ms-w32.h (struct timespec): Don't define if
+	_TIMESPEC_DEFINED is already defined.
+	(sigset_t) [!_POSIX]: Typedef for MinGW64.
+	(_WIN32_WINNT, WIN32_LEAN_AND_MEAN): Move definitions before
+	including the first system header, to avoid redefinition if some
+	system header defines a default value.
+
+	* inc/sys/time.h (struct itimerval): Don't define if
+	_TIMESPEC_DEFINED is already defined.
+
 2013-03-16  Eli Zaretskii  <eliz@gnu.org>
 
 	Fix the MSVC build.  (Bug#13939)

nt/inc/ms-w32.h

@@ -127,6 +127,15 @@ typedef unsigned short mode_t;
 extern char *getenv ();
 #endif
 
+/* Prevent accidental use of features unavailable in older Windows
+   versions we still support.  MinGW64 defines this to a higher value
+   in its system headers, so define our override before including any
+   system headers.  */
+#define _WIN32_WINNT 0x0400
+
+/* Make a leaner executable.  */
+#define WIN32_LEAN_AND_MEAN 1
+
 #ifdef HAVE_STRINGS_H
 #include "strings.h"
 #endif
@@ -266,11 +275,14 @@ int _getpid (void);
 /* 'struct timespec' is used by time-related functions in lib/ and
    elsewhere, but we don't use lib/time.h where the structure is
    defined.  */
+/* MinGW64 defines 'struct timespec' and _TIMESPEC_DEFINED in sys/types.h.  */
+#ifndef _TIMESPEC_DEFINED
 struct timespec
 {
   time_t	tv_sec;		/* seconds */
   long int	tv_nsec;	/* nanoseconds */
 };
+#endif
 
 /* Required for functions in lib/time_r.c, since we don't use lib/time.h.  */
 extern struct tm *gmtime_r (time_t const * restrict, struct tm * restrict);
@@ -321,6 +333,10 @@ typedef int sigset_t;
 typedef int ssize_t;
 #endif
 
+#ifndef _POSIX	/* MinGW64 */
+typedef _sigset_t sigset_t;
+#endif
+
 typedef void (_CALLBACK_ *signal_handler) (int);
 extern signal_handler sys_signal (int, signal_handler);
 
@@ -366,13 +382,6 @@ extern char *get_emacs_configuration_options (void);
 #define _WINSOCKAPI_    1
 #define _WINSOCK_H
 
-/* Prevent accidental use of features unavailable in
-   older Windows versions we still support.  */
-#define _WIN32_WINNT 0x0400
-
-/* Make a leaner executable.  */
-#define WIN32_LEAN_AND_MEAN 1
-
 /* Defines size_t and alloca ().  */
 #ifdef emacs
 #define malloc e_malloc

nt/inc/sys/time.h

@@ -23,11 +23,14 @@ void gettimeofday (struct timeval *, struct timezone *);
 #define ITIMER_REAL      0
 #define ITIMER_PROF      1
 
+/* MinGW64 defines 'struct itimerval' and _TIMESPEC_DEFINED in sys/types.h.  */
+#ifndef _TIMESPEC_DEFINED
 struct itimerval
 {
   struct  timeval it_interval;	/* timer interval */
   struct  timeval it_value;	/* current value */
 };
+#endif
 
 int getitimer (int, struct itimerval *);
 int setitimer (int, struct itimerval *, struct itimerval *);