Add system includes in sim

Add system includes in sim

This updates various parts of the sim to include missing system
headers.  I made the includes unconditional, because other parts of
the tree are already doing this.

2021-04-08  Tom Tromey  <tom@tromey.com>

	* traps.c: Include stdlib.h.
	* cris-tmpl.c: Include stdlib.h.

sim/erc32/ChangeLog
2021-04-08  Tom Tromey  <tom@tromey.com>

	* func.c: Include sys/time.h.

sim/frv/ChangeLog
2021-04-08  Tom Tromey  <tom@tromey.com>

	* traps.c: Include stdlib.h.
	* registers.c: Include stdlib.h.
	* profile.c: Include stdlib.h.
	* memory.c: Include stdlib.h.
	* interrupts.c: Include stdlib.h.
	* frv.c: Include stdlib.h.
	* cache.c: Include stdlib.h.

sim/iq2000/ChangeLog
2021-04-08  Tom Tromey  <tom@tromey.com>

	* iq2000.c: Include stdlib.h.

sim/m32r/ChangeLog
2021-04-08  Tom Tromey  <tom@tromey.com>

	* traps.c: Include stdlib.h.
	* m32r.c: Include stdlib.h.

sim/ppc/ChangeLog
2021-04-08  Tom Tromey  <tom@tromey.com>

	* emul_unix.c: Include time.h.