As an additional comment, it took me quite a while to find working values for

CFLAGS, AR, and LDFLAGS.  I'm not sure how you might accomplish it, but it would be
friendlier if, once it's determined that gcc is not available and xlC is available,
a reasonable set of default options were supplied, so that every user of xlC doesn't
have to rediscover some set defaults which allow the build to succeed.

Finally, I'm attaching the test-suite.log indicating a couple of failures and a few errors.