Maybe we should have a short snippet in our wiki with
what are appropriate
environment variables, which ones to avoid, and what
is appropriate for
CXX/CFLAGS?
Good idea! At least make mention of this problematic variable, as it took quite a while (and a couple of bug reports) for both of us to even begin to figure out what was going on. ;-)
I can add a snippet about the CPLUS_INCLUDE_PATH variable, but I don't the root cause of why the variable causes pkg-config to gag.
I'm nowhere close to being qualifed to write something about CXX/CFLAGS. Somebody else (not you) should provide a paragraph addressing those variables.
I don't know where to begin with respect to addressing other variables. Perhaps if several people here add their two cents or euros to what they use and what they avoid I then could massage that information into something useful. :)
Darrell