Zap some warnings in target files:

        * frame.c: Include stdlib.h and unistd.h to possibly get various
        function prototypes.  The fixproto script guarantees these header
        files exist on the target system.
        * libgcc2.c: Likewise.
        * gthr-single.h (__gthread_mutex_lock, __gthread_mutex_trylock,
        __gthread_mutex_unlock): Add __attribute__ ((__unused__)) to the
        function parameters.
        * libgcc2.c (__udiv_w_sdiv): Likewise.

From-SVN: r19261