ld: fix 6l -d on Mac, diagnose invalid use of -d

R=r
CC=golang-dev
https://golang.org/cl/4430064

src/cmd/ld/go.c

@@ -445,6 +445,12 @@ loaddynimport(char *file, char *pkg, char *p, int n)
 		*strchr(name, ' ') = 0;
 		*strchr(def, ' ') = 0;
 		
+		if(debug['d']) {
+			fprint(2, "%s: %s: cannot use dynamic imports with -d flag\n", argv0, file);
+			nerrors++;
+			return;
+		}
+		
 		if(strcmp(name, "_") == 0 && strcmp(def, "_") == 0) {
 			// allow #pragma dynimport _ _ "foo.so"
 			// to force a link of foo.so.
@@ -463,7 +469,7 @@ loaddynimport(char *file, char *pkg, char *p, int n)
 	return;
 
 err:
-	fprint(2, "%s: invalid dynimport line: %s\n", argv0, p0);
+	fprint(2, "%s: %s: invalid dynimport line: %s\n", argv0, file, p0);
 	nerrors++;
 }
 

src/cmd/ld/macho.c

@@ -349,11 +349,13 @@ asmbmacho(void)
 
 	msect = newMachoSect(ms, "__data");
 	msect->addr = va+v;
-	msect->size = symaddr(lookup(".got", 0)) - msect->addr;
 	msect->off = v;
+	msect->size = segdata.filelen;
 
 	s = lookup(".got", 0);
 	if(s->size > 0) {
+		msect->size = symaddr(s) - msect->addr;
+
 		msect = newMachoSect(ms, "__nl_symbol_ptr");
 		msect->addr = symaddr(s);
 		msect->size = s->size;