/usr/share/GNUstep/Makefiles/config.guess is in gnustep-common 2.6.1-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/share/GNUstep/Makefiles/../../misc/config.guess
/usr/share/GNUstep/Makefiles/../../misc/config.guess