Running go get golang.org/x/mobile/... results in errors because the
go tool fails to find the reverse generated Java ("Java/...") and
Objective-C ("ObjC/...") packages. Work around the errors by adding
the android and ios tags, respectively, to files importing those
packages.
The gobind gradle plugin is updated to pass along GOOS=android to
ensure the gobind tool continues to build Android reverse packages.
Fixesgolang/go#17750
Change-Id: Id66a3c6cdfe249c6ed494192eb12195d6509332f
Reviewed-on: https://go-review.googlesource.com/34956
Reviewed-by: David Crawshaw <crawshaw@golang.org>