Ensured all the system calls in msdfs.c go through the vfs layer.

Added vfs calls to symlink() and readlink() with appropriate configure
checks.
Jeremy.
(This used to be commit c24e6b41ea)

source3/lib/system.c

@@ -264,6 +264,34 @@ char *sys_getwd(char *s)
     return wd;
 }
 
+/*******************************************************************
+system wrapper for symlink
+********************************************************************/
+
+int sys_symlink(const char *oldpath, const char *newpath)
+{
+#ifndef HAVE_SYMLINK
+	errno = ENOSYS;
+	return -1;
+#else
+	return symlink(oldpath, newpath);
+#endif
+}
+
+/*******************************************************************
+system wrapper for readlink
+********************************************************************/
+
+int sys_readlink(const char *path, char *buf, size_t bufsiz)
+{
+#ifndef HAVE_READLINK
+	errno = ENOSYS;
+	return -1;
+#else
+	return readlink(path, buf, bufsiz);
+#endif
+}
+
 /*******************************************************************
 chown isn't used much but OS/2 doesn't have it
 ********************************************************************/