Add getcallerpc.
 [jmk] --rw-rw-r-- M 107020 jmk sys 50 Nov 19 20:14 sys/src/libc/68020/getcallerpc.s
 [jmk] --rw-rw-r-- M 107020 glenda sys 632 Nov 19 20:14 sys/src/libc/68020/mkfile
	/n/sourcesdump/2005/1119/plan9/sys/src/libc/68020/mkfile:4,9 - 
	/n/sourcesdump/2005/1120/plan9/sys/src/libc/68020/mkfile:4,10
	  LIB=/$objtype/lib/libc.a
	  SFILES=\
	  	argv0.s\
	+ 	getcallerpc.$O\
	  	getfcr.s\
	  	main9.s\
	  	main9p.s\
 [jmk] --rw-rw-r-- M 107020 jmk sys 48 Nov 19 20:12 sys/src/libc/arm/getcallerpc.s
 [jmk] --rw-rw-r-- M 107020 glenda sys 402 Nov 19 20:11 sys/src/libc/arm/mkfile
	/n/sourcesdump/2005/1119/plan9/sys/src/libc/arm/mkfile:5,10 - 
	/n/sourcesdump/2005/1120/plan9/sys/src/libc/arm/mkfile:5,11
	  SFILES=\
	  	argv0.s\
	  	div.s\
	+ 	getcallerpc.$O\
	  	getfcr.s\
	  	main9.s\
	  	main9p.s\
 [jmk] --rw-rw-r-- M 107020 jmk sys 49 Nov 19 20:14 sys/src/libc/sparc/getcallerpc.s
 [jmk] --rw-rw-r-- M 107020 glenda sys 451 Nov 19 20:15 sys/src/libc/sparc/mkfile
	/n/sourcesdump/2005/1119/plan9/sys/src/libc/sparc/mkfile:4,9 - 
	/n/sourcesdump/2005/1120/plan9/sys/src/libc/sparc/mkfile:4,10
	  LIB=/$objtype/lib/libc.a
	  SFILES=\
	  	argv0.s\
	+ 	getcallerpc.$O\
	  	getfcr.s\
	  	main9.s\
	  	main9p.s\