Don't return stack buffers.
 [rsc] --rw-rw-r-- M 771144 glenda sys 10238 Feb 11 18:11 sys/src/cmd/upas/smtp/spam.c
	/n/sourcesdump/2006/0211/plan9/sys/src/cmd/upas/smtp/spam.c:62,68 - 
	/n/sourcesdump/2006/0212/plan9/sys/src/cmd/upas/smtp/spam.c:62,68
	  char*
	  actstr(int a)
	  {
	- 	char buf[32];
	+ 	static char buf[32];
	  	Keyword *p;
	  
	  	for(p=actions; p->name; p++)