On a clean system without any port installed, a
cd /usr/ports/x11-fm/nautilus && make -DWITH_FULL_MOZILLA ends in
and error because of a lack of ghttp.h in include dirs.
Fix: Suggestion for an update of nautilus/Makefile
How-To-Repeat: Try to install mozilla without libghttp installed
Over to maintainers
Fixed, thanks for reporting.