nptl: mark forwarded functions protected
The libc stubs should never override the libpthread provided
functions inside libpthread, otherwise the struct pthread_functions
that is used by the forwarder stubs goes bad.
Signed-off-by: Timo Teras <timo.teras@iki.fi>
Signed-off-by: Austin Foxley <austinf@cetoncorp.com>