Issues with ports and clang cpp
- Clang cpp does not support the -traditional mode that exists in gcc, and will not grow support for this, since it is an old and mostly undocumented mode that exists only in gcc cpp.
It has been suggested that ucpp might be able to fill this void. After further investigation, this does not seem to always be the case.
- All ports using imake have issues, since imake uses cpp to create and format make files that are used during the build.
- Some ports, most notably libX11 and xorg-server has been patched to work around this issue
- The imake port itself has been patched to use ucpp during it's build, and is believed fixed; however, imake cannot compile graphics/xfig if imake was built with Clang. It is possible to get imake to use ucpp instead of cpp, however, ucpp is not compatible enough with gnu cpp -traditional behavior to be a viable replacement.
These were recent sightings on the FreeBSD-ports mailing list: