Two issues prevent the frv-elf port from building after the C99 changes. First
the trampoline code emitted into libgcc has calls to exit, but no prototype.
Adding a trivial prototype for exit() into the macro fixes that little goof.
Second, frvbegin.c has a call to atexit, so a quick prototype is added into
frvbegin.c to fix that problem.
That's enough to get the compiler building again.
gcc/
* config/frv/frv.h (TRANSFER_FROM_TRAMPOLINE): Add prototype for exit.
libgcc/
* config/frv/frvbegin.c (atexit): Add prototype.