Since bfloat16 and float16 support is not available for i386-freebsd,
the truncdfbf2.c and truncsfbf2.c builtin sources should be skipped
when targeting that platform, and COMPILER_RT_HAS_FLOAT16 should not
However, the CMake configuration stage runs its tests with the default
target, which normally is amd64-freebsd, so it will detect both bfloat16
and float16 support.
Move adding of the COMPILER_RT_HAS_FLOAT16 define to the foreach()
loop where all the supported architectures are handled, and do not
enable it when targeting i386-freebsd.
Also remove the bfloat16 sources from the i386_SOURCES list, when