[Bug preprocessor/122411] Empty path in COMPILER_PATH leads to -isystem ./include

[p.e.c.melis at alumnus dot utwente.nl via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122411

--- Comment #1 from Paul Melis <p.e.c.melis at alumnus dot utwente.nl> ---
This is on an Arch Linux x86_64 system, by the way, with the standard GCC
distro package.