Fix GCC build on Solaris
Fix GCC build on Solaris

Seems that upstream only build the C compiler on Solaris, as C++ builds were
broken.

CodethinkLabs/omnibus-codethink-toolchain,ssssam/omnibus-codethink-toolchain,CodethinkLabs/omnibus-codethink-toolchain,CodethinkLabs/omnibus-codethink-toolchain