poly1305/arm: allow building with Go 1.3

This is the same as https://golang.org/cl/154120043

Since the file textflag.h is not available on Go 1.3, the macros defined
in textflag.h are replaced with their respective value.

Fixes golang/go#11448

Change-Id: I0d4aed67b7afe50d8e4e88915edd2cefeac4cc96
Reviewed-on: https://go-review.googlesource.com/12033
Reviewed-by: Ian Lance Taylor <iant@golang.org>
1 file changed