devel/libffi: Fix abort() on ARM related to __clear_cache()
The current FreeBSD/ARM __clear_cache() implementation does nothing #if
__i386__ || __x86_64__ #else abort();
cognet@ advises this is an issue for anything !Apple that is using the
libcompiler_rt provided by Clang on ARM, and requires upstreaming.
Additionally, two Python ports (python26 and python31) use devel/libffi for
unrelated reasons, so this addresses the related PR for those ports too .
- Enable STAGE support
- Remove MAN* entries and update pkg-plist accordingly
- Add LICENSE
- Sort USE/USES section
- Use install-strip as the INSTALL_TARGET
PR: ports/184517 
Approved by: maintainer timeout (2 weeks)