Include a Makefile which contains some useful command lines Bug: angleproject:5697 Change-Id: I48c487d218183aa10823127beb40384f4debd6db Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2727921 Commit-Queue: Peng Huang <penghuang@chromium.org> Reviewed-by: Kenneth Russell <kbr@chromium.org>