unix: re-export Fsid and Sigset_t Val member on Linux

As spotted by Brad Fitzpatrick, CL 106838 unexported the value field of
Fsid and Sigset_t, but these types would be useless without any exported
fields. Re-export them via an exception in mkpost.go

Change-Id: I30d3c3b81c8c1b6377f8aa55cad816e3486a4395
Reviewed-on: https://go-review.googlesource.com/107415
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/unix/ztypes_linux_mipsle.go b/unix/ztypes_linux_mipsle.go
index 46fa3f9..67ac81e 100644
--- a/unix/ztypes_linux_mipsle.go
+++ b/unix/ztypes_linux_mipsle.go
@@ -172,7 +172,7 @@
 }
 
 type Fsid struct {
-	_ [2]int32
+	Val [2]int32
 }
 
 type Flock_t struct {
@@ -733,7 +733,7 @@
 )
 
 type Sigset_t struct {
-	_ [32]uint32
+	Val [32]uint32
 }
 
 const RNDGETENTCNT = 0x40045200