search for runtime.a in the package path instead of hardcoding
the location. remove last remnants of broken -l flag.

R=rsc
CC=golang-dev
https://golang.org/cl/201042
diff --git a/src/cmd/6l/obj.c b/src/cmd/6l/obj.c
index edae1c6..537ef9e 100644
--- a/src/cmd/6l/obj.c
+++ b/src/cmd/6l/obj.c
@@ -100,7 +100,9 @@
 	ARGBEGIN {
 	default:
 		c = ARGC();
-		if(c >= 0 && c < sizeof(debug))
+		if(c == 'l')
+			usage();
+ 		if(c >= 0 && c < sizeof(debug))
 			debug[c]++;
 		break;
 	case 'o': /* output to (next arg) */
@@ -131,7 +133,6 @@
 		break;
 	case 'u':	/* produce dynamically loadable module */
 		dlm = 1;
-		debug['l']++;
 		if(argv[1] != nil && argv[1][0] != '-' && !isobjfile(argv[1]))
 			readundefs(ARGF(), SIMPORT);
 		break;
@@ -347,9 +348,7 @@
 	lastp = firstp;
 
 	addlibpath("command line", "command line", argv[0], "main");
-
-	if(!debug['l'])
-		loadlib();
+	loadlib();
 
 	deadcode();