Work around a gcc 4.2 bug on powerpc architectures, where using

Work around a gcc 4.2 bug on powerpc architectures, where using
-fdata-sections can cause bogus "section type conflict" errors.  See
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=33168 for more information.

Since the upstream fixes are under GPLv3 and non-trivial, just disable
using function and data sections, at the cost of a slightly larger
executable.

Direct commit to stable/10, since the version of clang in head and
stable/11 cannot be built by gcc 4.2 at all.

git-svn-id: svn://svn.freebsd.org/base/stable/10@319631 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f