cc/gcc: fix gcc 4.8 build for C library without threads support

Signed-off-by: Niels Penneman <niels@penneman.org>
Message-Id: <309df93f4354c80e05c9.1388743085@i7sb.local>
Patchwork-Id: 306521

reporter_name="Yann E. MORIN"

reporter_url="http://ymorin.is-a-geek.org/projects/crosstool"

reporter_comment="EXPERIMENTAL MIPS-64 n64 toolchain."