during stage building process, gcc-config is building before openrc (openrc is not even building into stage1). After gcc building, gcc-config runs, which checks for /etc/init.d/functions.sh, this script belongs to openrc and obviously it's not there. This script is important and many programs look for it (gentoolkit, perl-cleaner, gcc-config). Here is the corresponding gentoo bug thread https://bugs.gentoo.org/show_bug.cgi?id=373219

Excerpt from metro log:

>>> Regenerating /etc/ld.so.cache...
/usr/bin/gcc-config: line 19: /etc/init.d/functions.sh: No such file or directory
gcc-config: Could not source /etc/init.d/functions.sh!