Don't set CPLUS_INCLUDE_PATH?
I am now doing that. :)
Seriously, I'm not sure why you set that variable. I never heard of it before, and usually the safest way to get includes added to the compiler flags is via CXXFLAGS and CFLAGS.
Long ago in a galaxy far away, when I first joined the project, I noticed the variable being set in the /etc/profile.d/qt.sh script that came with the Slackware qt3 package. I presumed the variable was important. Of course, that script is for run time and not for compiling. Over time I have been learning to strip many environment variables from within my build environment, but that one slipped through unnoticed until this mess surfaced.
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?
If you have a specific reason for setting CPLUS_INCLUDE_PATH then that is different.
Not any more! :)
Darrell