I'm compiling on Arch Linux, and am getting dependencies from Arch's package manager. Headers are stored in /usr/include. I've configured all my header directories using the helpful instructions at the top of the Makefile.

However, I run into errors that stdlib.h cannot be found. I traced it to this issue: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70129#c1

So I've gone and commented out most of the *_INCL_DIR variables, since they end up in -isystem arguments. That works, for the most part, except when those variables are needed for other reasons, in which case I go and delete the -isystem line.

I've been able to get openvdb to compile, but am not sure how I'd fix the Makefile to handle more general cases, like people using gcc < 6

Any advice?