Don't profile getcallerpc.
 [rsc] --rw-rw-r-- M 1428987 glenda sys 52 Jan 28 10:48 sys/src/libc/power/getcallerpc.s
	/n/sourcesdump/2006/0128/plan9/sys/src/libc/power/getcallerpc.s:1,4 - 
	/n/sourcesdump/2006/0129/plan9/sys/src/libc/power/getcallerpc.s:1,4
	- TEXT	getcallerpc(SB), $-4
	+ TEXT	getcallerpc(SB),1,$-4
	  	MOVW	0(R1), R3
	  	RETURN