remove 8.out before creating it.

hope this will work around Mac NFS bug
where writing to an 8.out that has crashed
recently sometimes wedges NFS.

R=r
DELTA=3  (3 added, 0 deleted, 0 changed)
OCL=32906
CL=32908

src/cmd/5l/obj.c

@@ -252,6 +252,7 @@ main(int argc, char *argv[])
 	dtype = 4;
 	if(outfile == 0)
 		outfile = "5.out";
+	unlink(outfile);
 	cout = create(outfile, 1, 0775);
 	if(cout < 0) {
 		diag("%s: cannot create", outfile);

src/cmd/6l/obj.c

@@ -337,6 +337,7 @@ main(int argc, char *argv[])
 	edatap = P;
 	pc = 0;
 	dtype = 4;
+	unlink(outfile);
 	cout = create(outfile, 1, 0775);
 	if(cout < 0) {
 		diag("cannot create %s", outfile);

src/cmd/8l/obj.c

@@ -306,6 +306,7 @@ main(int argc, char *argv[])
 	edatap = P;
 	pc = 0;
 	dtype = 4;
+	unlink(outfile);
 	cout = create(outfile, 1, 0775);
 	if(cout < 0) {
 		diag("cannot create %s", outfile);