Tweaks to various bits.

Until I hear otherwise, Refs aren't used enough to
merit their own assembly.  They are now implemented with locks.

src/libthread/asm-FreeBSD-386.s

@@ -30,20 +30,20 @@ _gotolabel:
 	ret
 
 
-.globl	_xinc
-_xinc:
-	movl 4(%esp), %eax
-	lock incl 0(%eax)
-	ret
-
-.globl	_xdec
-_xdec:
-	movl 4(%esp), %eax
-	lock decl 0(%eax)
-	jz iszero
-	movl $1, %eax
-	ret
-iszero:
-	movl $0, %eax
-	ret
-
+# .globl	_xinc
+# _xinc:
+# 	movl 4(%esp), %eax
+# 	lock incl 0(%eax)
+# 	ret
+# 
+# .globl	_xdec
+# _xdec:
+# 	movl 4(%esp), %eax
+# 	lock decl 0(%eax)
+# 	jz iszero
+# 	movl $1, %eax
+# 	ret
+# iszero:
+# 	movl $0, %eax
+# 	ret
+# 

src/libthread/exec-unix.c

@@ -122,6 +122,7 @@ efork(void *ve)
 	for(i=3; i<40; i++)
 		if(i != e->fd[1])
 			close(i);
+	rfork(RFNOTEG);
 	execvp(e->prog, e->args);
 	_threaddebug(DBGEXEC, "_schedexec failed: %r");
 	rerrstr(buf, sizeof buf);

src/libthread/ref.c

@@ -3,11 +3,18 @@
 void
 incref(Ref *r)
 {
-	_xinc(&r->ref);
+	lock(&r->lk);
+	r->ref++;
+	unlock(&r->lk);
 }
 
 long
 decref(Ref *r)
 {
-	return _xdec(&r->ref);
+	long n;
+
+	lock(&r->lk);
+	n = --r->ref;
+	unlock(&r->lk);
+	return n;
 }