Merge remote-tracking branch 'remotes/philmd-gitlab/tags/edk2-next-20191007' into...

Merge remote-tracking branch 'remotes/philmd-gitlab/tags/edk2-next-20191007' into staging

Improve scripts relying on the EDK2 submodule,
drop Python2 dependency in EDK2 build scripts.

# gpg: Signature made Mon 07 Oct 2019 14:31:38 BST
# gpg:                using RSA key 89C1E78F601EE86C867495CBA2A3FD6EDEADC0DE
# gpg: Good signature from "Philippe Mathieu-Daudé (Phil) <philmd@redhat.com>" [marginal]
# gpg: WARNING: This key is not certified with sufficiently trusted signatures!
# gpg:          It is not certain that the signature belongs to the owner.
# Primary key fingerprint: 89C1 E78F 601E E86C 8674  95CB A2A3 FD6E DEAD C0DE

* remotes/philmd-gitlab/tags/edk2-next-20191007:
  edk2 build scripts: work around TianoCore#1607 without forcing Python 2
  edk2 build scripts: honor external BaseTools flags with uefi-test-tools
  roms: Add a 'make help' target alias
  roms/Makefile.edk2: don't pull in submodules when building from tarball
  make-release: pull in edk2 submodules so we can build it from tarballs

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>