Don't use CONFIG_CC_IS_GCC in the checks (it was introduced only in v4.18)
drwxr-xr-x - .github
-rw-r--r-- 1802 .gitignore
-rw-r--r-- 35147 LICENSE.txt
-rw-r--r-- 81 MANIFEST.in
-rw-r--r-- 26556 README.md
drwxr-xr-x - bin
-rw-r--r-- 170 default.nix
drwxr-xr-x - kconfig_hardened_check
-rw-r--r-- 818 setup.cfg
-rwxr-xr-x 259 setup.py