Synced bcompat tree additions and fixes found so far

amxmodx/amx.h

@@ -322,6 +322,7 @@ enum {
 #define AMX_FLAG_COMPACT  0x04  /* compact encoding */
 #define AMX_FLAG_BYTEOPC  0x08  /* opcode is a byte (not a cell) */
 #define AMX_FLAG_NOCHECKS 0x10  /* no array bounds checking; no STMT opcode */
+#define AMX_FLAG_OLDFILE  0x20	/* Old AMX Mod plugin */
 #define AMX_FLAG_PRENIT	 0x100	/* pre-initialized, do not check natives */
 #define AMX_FLAG_NTVREG 0x1000  /* all native functions are registered */
 #define AMX_FLAG_JITC   0x2000  /* abstract machine is JIT compiled */