/usr/include/GNUstep/Pantomime is in libpantomime1.2-dev 1.2.0~pre3+snap20071004+dfsg-4build1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/include/GNUstep/../../lib/GNUstep/Frameworks/Pantomime.framework/Headers