Move SET_LATE_CONFIGURE_ARGS into a script to reduce executions.

[bdrewery]

Summary

The goal of this is to only run './configure --help' once, rather than
N times for each option we're looking for.

While here I noticed that the --build support for >autoconf-2.13 from
r218938 and r219124 was not quite right. This requires further
investigation and a separate fix.

This also includes --enable-jobserver which has an EXP-RUN request
at https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=217670

[bdrewery]

Fix build with ports not using GNU_CONFIGURE but with HAVE_CONFIGURE, like perl. They don't set the _LATE_CONFIGURE_ARGS so the ';' have to move back.

[antoine]

Mk/Scripts/set-late-configure-args.sh

43

with --verison, but with --version?

here it says:

% ./configure --version
configure generated by autoconf version 2.13

45

with --verison, but with --version??

[bdrewery]

Remove bogus comment due to typo in testing.

[mat]

Mk/Scripts/set-late-configure-args.sh

26

So, we can see where you copied that from, should be DEBUG_MK_SCRIPTS_LATE_CONFIGURE_ARGS or something similar :)

32

empty line?

48

Mmm, maybe quote "${dp_CONFIGURE_CMD}" in there, in case there is space or something in there.

78

same here ?

[bdrewery]

Review findings