Print to diagbuf so that prints stay together.
 [rsc] --rw-rw-r-- M 129339 glenda sys 26837 Dec 12 07:21 sys/src/cmd/cc/dcl.c
	/n/sourcesdump/2005/1212/plan9/sys/src/cmd/cc/dcl.c:1324,1331 - 
	/n/sourcesdump/2005/1213/plan9/sys/src/cmd/cc/dcl.c:1324,1331
	  	if(s->type != T)
	  		if(s->class != c || !sametype(t, s->type) || t->etype == TENUM) {
	  			diag(Z, "external redeclaration of: %s", s->name);
	- 			print("	%s %T %L\n", cnames[c], t, nearln);
	- 			print("	%s %T %L\n", cnames[s->class], s->type, s->varlineno);
	+ 			Bprint(&diagbuf, "	%s %T %L\n", cnames[c], t, nearln);
	+ 			Bprint(&diagbuf, "	%s %T %L\n", cnames[s->class], s->type, s->varlineno);
	  		}
	  	tmerge(t, s);
	  	s->type = t;