Fixed error: conflicting types for 'getpagesize'

src/stdlib/SDL_malloc.c

@@ -1590,7 +1590,7 @@ unsigned char _BitScanReverse(unsigned long *index, unsigned long mask);
 #    define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
 #  else
 #    if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
-       extern size_t getpagesize();
+       extern int getpagesize();
 #      define malloc_getpagesize getpagesize()
 #    else
 #      ifdef WIN32 /* use supplied emulation of getpagesize */