New optimization option for testing

Using gcc's option '-Og' (instead of '-O0') for testing/debugging.

makefile

@@ -63,7 +63,7 @@ CWARNS= $(CWARNSCPP) $(CWARNSC) $(CWARNGCC)
 # ASAN_OPTIONS="detect_invalid_pointer_pairs=2".
 # -fsanitize=undefined
 # -fsanitize=pointer-subtract -fsanitize=address -fsanitize=pointer-compare
-# TESTS= -DLUA_USER_H='"ltests.h"' -O0 -g
+# TESTS= -DLUA_USER_H='"ltests.h"' -Og -g
 
 
 LOCAL = $(TESTS) $(CWARNS)