bug#79344: Unexpected test failures: automake 1.18.1 and macOS 15.6.1

Hi Eric,

    Three of those appear to be in the t/tap-stderr-prefix tests and the
    other for t/yacc-bison-skeleton.  A gzipped version of
    test-suite.log, trimmed to the output for the four unexpected
    failures, is attached.

Thanks for the report. I'll look into it as soon as I can, if no one
else gets there first. --best, karl.