handle very long symbol names.  via cinap.

Reference: /n/atom/patch/applied2013/acidlongsym
Date: Thu Oct  3 17:12:34 CES 2013
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/acid/util.c	Thu Oct  3 17:11:46 2013
+++ /sys/src/cmd/acid/util.c	Thu Oct  3 17:11:46 2013
@@ -9,14 +9,19 @@
 
 static int syren;
 
+enum {
+	Renames	= 5,
+};
+
 Lsym*
-unique(char *buf, Sym *s)
+unique(char *buf, int bufsz, Sym *s)
 {
 	Lsym *l;
 	int i, renamed;
 
 	renamed = 0;
-	strcpy(buf, s->name);
+	strncpy(buf, s->name, bufsz - Renames - 1);
+	buf[bufsz - Renames - 1] = 0;
 	for(;;) {
 		l = look(buf);
 		if(l == 0 || (l->lexval == Tid && l->v->set == 0))
@@ -30,7 +35,7 @@
 		memmove(buf+1, buf, i);
 		buf[0] = '$';
 		renamed++;
-		if(renamed > 5 && !quiet) {
+		if(renamed > Renames && !quiet) {
 			print("Too many renames; must be X source!\n");
 			break;
 		}
@@ -76,7 +81,7 @@
 			*tail = tl;
 			tail = &tl->next;
 
-			l = unique(buf, s);
+			l = unique(buf, sizeof buf, s);
 
 			l->v->set = 1;
 			l->v->type = TINT;