move id check to lib.sh too

doesn't really matter, it's just an extra layer to ensure
reliability, but "id" is pretty standard

Signed-off-by: Leah Rowe <leah@libreboot.org>

include/lib.sh

@@ -61,6 +61,7 @@ install_packages()
 }
 [ $# -gt 0 ] && [ "$1" = "dependencies" ] && install_packages $@ && return 0
 
+id -u 1>/dev/null 2>/dev/null || $err "suid check failed (id -u)"
 [ "$(id -u)" != "0" ] || $err "this command as root is not permitted"
 
 # if "y": a coreboot target won't be built if target.cfg says release="n"