component/golang: support compilation on aarch64

See merge request nexedi/slapos!1317

component/golang/buildout.cfg

@@ -48,11 +48,20 @@ md5sum = dbf727a4b0e365bf88d97cbfde590016
 environment-extra =
 # build Go without testing it
 # NOTE go1.4 does not have build cache
-make-targets= cd src && unset GOBIN && ./make.bash && cp -alf .. ${:location}
+setarch =
+make-targets= cd src && unset GOBIN && ${:setarch} ./make.bash && cp -alf .. ${:location}
+
+# go1.4 is used for bootstrap and does not support CGO
+environment-extra =
+  CGO_ENABLED=0
 
 # skip-chown-tests.patch does not apply to go1.4, but we don't run go1.4 tests.
 patches =
 
+# go1.4 does not have support for arm64 - build it in arm32 mode
+[golang14:platform.machine() == 'aarch64']
+setarch = setarch arm
+
 
 [golang1.12]
 <= golang-common