script/unit-test: Fix autoconf detection

Instead of parsing the autoconf file by hand, let autoconf do all of the
heavy lifting. This change rewrite the get_autoconf_deps function to
invoke autoconf, and parse the resulting strings out. This has the
benefit of not needing to understand any of the m4 formatting in our own
python code.

Tested:
    Against sdeventplus which has no dependencies and against
    phosphor-net-ipmid which requires phosphor-host-ipmid to build.
    Dependencies were detected and built successfully.

Change-Id: I33d6db730cc0b6b896464fc22bed6ff77af85d5b
Signed-off-by: William A. Kennington III <wak@google.com>
1 file changed