Well, for skalibs in particular, that happens to work, since you (for some reason) add -fno-stack-protector to CPPFLAGS, and CFLAGS happens to come after in the compile rule. But for e.g. s6 and s6-rc, you append fno-stack-protector to CFLAGS, so it doesn't matter what CFLAGS contained at configure time; your setting overrides that (and not the other way around).
Hm, that is a problem indeed. The goal is always for the user CFLAGS to override the automatic CFLAGS. I'm going to fix that. Thanks for the report! -- Laurent
