build-unit-test-docker: Temporarily drop libpldm test configuration

The series at [1] switches libpldm's 'test' option type from feature to
boolean. Avoid the container build error in the interim by not disabling
the build of the tests, however, in doing so, ensure that the test build
dependencies are available to meson. The change implements the latter
by allowing the gtest and gmock wraps to download their sources during
the build.

The holistic approach of this patch is a compromise against the effort
required to allow type detection for meson flags, like we do in scripts/
unit-test.py. That code could be made common, however the work is a
bunch of refactoring that ultimately loses value once the patch to
change the test option type to boolean is merged in libpldm. Once
the patch is merged, we can drop `--wrap-mode=default` and introduce
`-Dtests=false` as the replacement for `-Dtests=disabled`.

[1]: https://gerrit.openbmc.org/q/topic:%22options-rework%22+repo:openbmc/libpldm

Change-Id: I51e51c75603db613aac3bd11c719def4b7e23561
Signed-off-by: Andrew Jeffery <andrew@codeconstruct.com.au>
1 file changed