unit-test: Define TEST_ONLY=1 to skip the analyse phase

The autotools build system driver was doing something quite different to
CMake and Meson. This makes it hard to document the behaviour of
TEST_ONLY=1.

Give it the consistent behaviour of skipping the analyse() phase in the
BuildSystem implementation.

Change-Id: I3a8986899cb96d274932263647e8a8b18fbeed49
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
1 file changed