x/mobile/gl: include textflag.h in work_windows_amd64.s

Fixes golang/go#13649

Change-Id: Ic552c74489e6aa11c0d2316073f623e2936d608d
Reviewed-on: https://go-review.googlesource.com/17922
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
diff --git a/gl/work_windows_amd64.s b/gl/work_windows_amd64.s
old mode 100755
new mode 100644
index 55a9718..e74ac5c
--- a/gl/work_windows_amd64.s
+++ b/gl/work_windows_amd64.s
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+#include "textflag.h"
+
 TEXT ·fixFloat(SB),NOSPLIT,$0-32
 	MOVQ 	x0+0(FP), X0
 	MOVQ	x1+8(FP), X1