How come src/post_modules/GL/Makefile.in and src/post_modules/GTK2/Makefile.in delete -g*, -W*, and -O* flags from CFLAGS? efb49e63aff070c by Grubba on 2000-09-02 only says "Attempt at fixing a few warnings" and ed4662949516b507 by Per on 1999-11-20 is even terser with "Fixed makefile" (that's from the GTK 1 module).
By contrast, GLUT's makefile doesn't do this.
