libgo: update to go1.7rc3

Change-Id: I2ffbdf95fd9e105c6059e9886b6c7d2ef2071c83
Reviewed-on: https://go-review.googlesource.com/25150
Reviewed-by: Ian Lance Taylor <iant@golang.org>
diff --git a/libgo/go/syscall/dir_plan9.go b/libgo/go/syscall/dir_plan9.go
index 697bf54..15b2674 100644
--- a/libgo/go/syscall/dir_plan9.go
+++ b/libgo/go/syscall/dir_plan9.go
@@ -184,6 +184,7 @@
 }
 
 // gbit16 reads a 16-bit number in little-endian order from b and returns it with the remaining slice of b.
+//go:nosplit
 func gbit16(b []byte) (uint16, []byte) {
 	return uint16(b[0]) | uint16(b[1])<<8, b[2:]
 }