gcc-target.inc: Remove non-related gcc headers from include_fixed folder
Without this patch, the D's include_fixed folder may change after building it
(due to the gcc's fixinc.sh script, executed on the do_compile task) and changes
depend on the current sysroot headers, making the gcc's builds non-deterministic.
[YOCTO #7882]
Signed-off-by: Leonardo Sandoval <leonardo.sandoval.gonzalez@linux.intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
