Use the serial automake test harness
Once upon a time, automake had one way to run tests. Apparently this is (nowadays?) called the serial test harness. Then, in some release (I do not remember which one), the parallel test harness became the default.
The parallel harness runs all tests in parallel, but does not (really) show the test output, but instead has output redirected to files. Sort of. I did not find the result of my printf() anywhere.
The automake docs strongly discourage using the serial test harness 0, but do not really say why. For cairo, I do not see problems:
We have some quick, small checks (e.g. is cairo_public used where needed in the public headers). And then there is the big, heavy-weight test suite (cairo-test-suite). Thus, running these things in parallel has basically no benefits.
Additionally, cairo-test-suite takes really, really long. Not seeing any output while it is running is annoying. Failing to find the output even in files is bad.
Thus, since I do not see any benefits and only downsides to the parallel test harness, this commit switches to the serial one.
Signed-off-by: Uli Schlachter email@example.com