prims.cc (unblock_signal): Annotate signum with __unused__ to avoid warnings in the non-POSIX_VERSION case.


	* prims.cc (unblock_signal): Annotate signum with __unused__ to
	avoid warnings in the non-POSIX_VERSION case.
	Also, we only need this function if either HANDLE_SEGV or HANDLE_FPE,
	so place it inside an #if block.
	* include/default-signal.h (SIGNAL_HANDLER): Parameters are __unused__.
	* include/i386-signal.h (SIGNAL_HANDLER):  Likewise
	* include/mips-signal.h (SIGNAL_HANDLER):  Likewise
	* include/sparc-signal.h (SIGNAL_HANDLER):  Likewise

From-SVN: r88148