Some Makefiles clear out MOZ_GLUE_LDFLAGS and/or STL_FLAGS, which are set from autoconf.mk. We need a way to support this in moz.build. I'd guess the easiest way is a flag that can be set to True which will clear MOZ_GLUE_LDFLAGS / STL_FLAGS in config.mk, but if anyone has a better idea feel free to chime in.

This sounds like what I did to migrate VISIBILITY_FLAGS in bug 930674.

Whoops, you'd think I'd remember that given the reviewer... Sounds like that's the way to go for these two then.

I think we should do it more semantically, instead of blindly adding variables for that. To do that, we need to answer a few questions: - Are we ever setting those variables to a value, or just resetting them? - Are we ever (re)setting one and not the other? - Where are they used, and for what purpose?

This was fixed by one of the linking bugs at some point in time, and I don't care to track it down.