Conditionalize MAX_WIDTH / MAX_HEIGHT defines so that users can
set them via CFLAGS.
/**
* Maximum viewport/image width. Must accomodate all texture sizes too.
*/
-#define MAX_WIDTH 4096
+
+#ifndef MAX_WIDTH
+# define MAX_WIDTH 4096
+#endif
/** Maximum viewport/image height */
-#define MAX_HEIGHT 4096
+#ifndef MAX_HEIGHT
+# define MAX_HEIGHT 4096
+#endif
/** Maxmimum size for CVA. May be overridden by the drivers. */
#define MAX_ARRAY_LOCK_SIZE 3000