Enable debug when compiling custom package

Currently, my custom package crashes and when I used gdb on the resulting core file, it states that "no debugging symbols found in" my executable (the one in the build_dir not the ipk file).
I have tried adding RSTRIP:=: to no avail (I wonder if this only affects the ipk file and not the binary file in build_dir). I have read that the gcc option -g may help. Problem is where do I add this option?