scripts/unit-test: Only use defined meson options

Currently, our meson configuration assumes that some package specific
options are defined for all packages. This parses the options file and
only includes options which are defined.

Tested:
    Ran against sdeventplus and phosphor-host-ipmid to verify that both
    flags were passed to sdeventplus and only the test flag was passed
    to host-ipmid.

Change-Id: Ia0c7ee4ee025658c46484dcfaa119dec39c1e249
Signed-off-by: William A. Kennington III <wak@google.com>
1 file changed