gallium: Use the custom snprintf implementation everywhere (for Win32).

Because winddk's implemenation does not handle floats.

src/gallium/include/pipe/p_util.h

@@ -32,6 +32,7 @@
 #include "p_debug.h"
 #include "p_pointer.h"
 #include <math.h>
+#include <stdarg.h>
 
 
 #ifdef __cplusplus
@@ -137,6 +138,14 @@ REALLOC( void *old_ptr, unsigned old_size, unsigned new_size )
 #define GETENV( X ) debug_get_option( X, NULL )
 
 
+#ifdef WIN32
+int rpl_vsnprintf(char *, size_t, const char *, va_list);
+int rpl_snprintf(char *str, size_t size, const char *format, ...);
+#define vsnprintf rpl_vsnprintf
+#define snprintf rpl_snprintf
+#endif
+
+
 /**
  * Return memory on given byte alignment
  */