Replace X-allocation functions with their C89 counterparts

The only remaining X-functions used in server are XNF*, the rest is converted to
plain alloc/calloc/realloc/free/strdup.

X* functions are still exported from server and x* macros are still defined in
header file, so both ABI and API are not affected by this change.

Signed-off-by: Mikhail Gusarov <dottedmag@dottedmag.net>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>

glx/unpack.h

@@ -86,7 +86,7 @@ extern xGLXSingleReply __glXReply;
     if ((size) > sizeof(answerBuffer)) {				 \
 	int bump;							 \
 	if ((cl)->returnBufSize < (size)+(align)) {			 \
-	    (cl)->returnBuf = (GLbyte*)Xrealloc((cl)->returnBuf,	 \
+	    (cl)->returnBuf = (GLbyte*)realloc((cl)->returnBuf,	 	 \
 						(size)+(align));         \
 	    if (!(cl)->returnBuf) {					 \
 		return BadAlloc;					 \