go.crypto: add and adjust +build lines for 386 and gccgo

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/6827061

curve25519/const_amd64.s

@@ -5,6 +5,8 @@
 // This code was translated into a form compatible with 6a from the public
 // domain sources in SUPERCOP: http://bench.cr.yp.to/supercop.html
 
+// +build amd64,!gccgo
+
 DATA ·REDMASK51(SB)/8, $0x0007FFFFFFFFFFFF
 GLOBL ·REDMASK51(SB), $8
 

curve25519/cswap_amd64.s

@@ -5,6 +5,8 @@
 // This code was translated into a form compatible with 6a from the public
 // domain sources in SUPERCOP: http://bench.cr.yp.to/supercop.html
 
+// +build amd64,!gccgo
+
 // func cswap(inout *[5]uint64, v uint64)
 TEXT ·cswap(SB),7,$0
 	MOVQ inout+0(FP),DI

curve25519/curve25519.go

@@ -3,8 +3,8 @@
 // license that can be found in the LICENSE file.
 
 // We have a implementation in amd64 assembly so this code is only run on
-// non-amd64 platforms.
-// +build !amd64
+// non-amd64 platforms.  The amd64 assembly does not support gccgo.
+// +build !amd64 gccgo
 
 package curve25519
 

curve25519/freeze_amd64.s

@@ -5,6 +5,8 @@
 // This code was translated into a form compatible with 6a from the public
 // domain sources in SUPERCOP: http://bench.cr.yp.to/supercop.html
 
+// +build amd64,!gccgo
+
 // func freeze(inout *[5]uint64)
 TEXT ·freeze(SB),7,$96-8
 	MOVQ inout+0(FP), DI

curve25519/ladderstep_amd64.s

@@ -5,6 +5,8 @@
 // This code was translated into a form compatible with 6a from the public
 // domain sources in SUPERCOP: http://bench.cr.yp.to/supercop.html
 
+// +build amd64,!gccgo
+
 // func ladderstep(inout *[5][5]uint64)
 TEXT ·ladderstep(SB),0,$384-8
 	MOVQ inout+0(FP),DI

curve25519/mont25519_amd64.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build amd64,!gccgo
+
 package curve25519
 
 // These functions are implemented in the .s files. The names of the functions

curve25519/mul_amd64.s

@@ -5,6 +5,8 @@
 // This code was translated into a form compatible with 6a from the public
 // domain sources in SUPERCOP: http://bench.cr.yp.to/supercop.html
 
+// +build amd64,!gccgo
+
 // func mul(dest, a, b *[5]uint64)
 TEXT ·mul(SB),0,$128-24
 	MOVQ dest+0(FP), DI

curve25519/square_amd64.s

@@ -5,6 +5,8 @@
 // This code was translated into a form compatible with 6a from the public
 // domain sources in SUPERCOP: http://bench.cr.yp.to/supercop.html
 
+// +build amd64,!gccgo
+
 // func square(out, in *[5]uint64)
 TEXT ·square(SB),7,$96-16
 	MOVQ out+0(FP), DI

poly1305/const_amd64.s

@@ -5,6 +5,8 @@
 // This code was translated into a form compatible with 6a from the public
 // domain sources in SUPERCOP: http://bench.cr.yp.to/supercop.html
 
+// +build amd64,!gccgo
+
 DATA ·SCALE(SB)/8, $0x37F4000000000000
 GLOBL ·SCALE(SB), $8
 DATA ·TWO32(SB)/8, $0x41F0000000000000

poly1305/poly1305_amd64.s

@@ -5,6 +5,8 @@
 // This code was translated into a form compatible with 6a from the public
 // domain sources in SUPERCOP: http://bench.cr.yp.to/supercop.html
 
+// +build amd64,!gccgo
+
 // func poly1305(out *[16]byte, m *byte, mlen uint64, key *[32]key)
 TEXT ·poly1305(SB),0,$224-32
 	MOVQ out+0(FP),DI

poly1305/sum_amd64.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// +build amd64,!gccgo
+
 package poly1305
 
 // This function is implemented in poly1305_amd64.s

poly1305/sum_ref.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !amd64
+// +build !amd64 gccgo
 
 package poly1305
 

salsa20/salsa/salsa2020_amd64.s

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !appengine
+// +build amd64,!appengine,!gccgo
 
 // This code was translated into a form compatible with 6a from the public
 // domain sources in SUPERCOP: http://bench.cr.yp.to/supercop.html

salsa20/salsa/salsa20_amd64.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !appengine
+// +build amd64,!appengine,!gccgo
 
 package salsa
 

salsa20/salsa/salsa20_ref.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-// +build !amd64 appengine
+// +build !amd64 appengine gccgo
 
 package salsa