This is a preparation to enable Go modules for gomobile commands.
When Go modules is used, $GOPATH is not available. To build a
local package with Go modules, changing the working directory and
specifying the package by a relative path begining with `./` is
required. Changing the working directory is necessary because
building outside of modules is forbidden.
Specifying $GOPATH is still needed for reverse bindings (i.e.
special packages begining with `Java/` or `ObjC/`). Note that
gomobile with Go modules cannot support reverse bindings so far.
Updates golang/go#27234
Change-Id: Ib19300e1b8a973e76e06d24472c63a98605d65f7
Reviewed-on: https://go-review.googlesource.com/c/mobile/+/209137
Run-TryBot: Hajime Hoshi <hajimehoshi@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
5c0e7e404a