Remove _LARGEFILE_SOURCE64 usage

Typo of actual macro _LARGEFILE64_SOURCE.
There is no usage of the features provided by _LARGEFILE64_SOURCE
present in Allegro, otherwise there would likely also be compiler
warnings/errors regarding implicit function declarations and
unknown types.

Author: chrstphrchvz

src/file_stdio.c

@@ -20,9 +20,6 @@
 #ifndef _LARGEFILE_SOURCE
    #define _LARGEFILE_SOURCE
 #endif
-#ifndef _LARGEFILE_SOURCE64
-   #define _LARGEFILE_SOURCE64
-#endif
 #ifndef _FILE_OFFSET_BITS
    #define _FILE_OFFSET_BITS 64
 #endif

src/fshook_stdio.c

@@ -35,7 +35,6 @@ ALLEGRO_DEBUG_CHANNEL("fshook")
 /* Enable large file support in gcc/glibc. */
 #if defined ALLEGRO_HAVE_FTELLO && defined ALLEGRO_HAVE_FSEEKO
    #define _LARGEFILE_SOURCE
-   #define _LARGEFILE_SOURCE64
    #define _FILE_OFFSET_BITS 64
 #endif