The Apple-backed Clang compiler is now the default compiler in FreeBSD.
One of the tentative goals for the upcoming FreeBSD 10 release is for BSD's base system to be totally free of code licensed under the GPL.
That goal took a massive step forward this week with the announcement that Clang is now the default compiler on x86 builds of FreeBSD, replacing the GPL-licensed GCC compiler.
"There will probably be a few bumps as we work out the last kinks, including a ABI issue for i386 system libraries, but the transition is expected to be fairly smooth for most users," wrote FreeBSD core team member Brooks Davis.
Besides its BSD licensing, Clang, along with its LLVM back end, provides better integration with IDEs by making it easier to map errors back to the offending piece of code better than GCC can. Clang is already used in Apple's XCode.
For philosophical reasons regarding the GPLv3, FreeBSD has been officially using an outdated version of GCC (4.2.1) in its releases for some time, although there was nothing holding back users wanting to update the GCC compiler to later versions themselves.