support vfork on i386

src/process/i386/vfork.s

@@ -0,0 +1,14 @@
+.global __vfork
+.weak vfork
+.type __vfork,@function
+.type vfork,@function
+__vfork:
+vfork:
+	pop %edx
+	mov $190,%eax
+	int $128
+	push %edx
+	push %eax
+	call __syscall_ret
+	pop %edx
+	ret