Automated fix for automake 1.13 changes

[Ryan Schmidt]

As was remarked earlier, there seem to be a lot of packages affected by the automake 1.13 changes, mainly the change from AM_CONFIG_HEADER to AC_CONFIG_HEADERS. In #37712 it was suggested that we should have a way to fix all of these ports at once.

https://trac.macports.org/ticket/37712

I initially said I wasn't sure how we would do that, so I thought I'd throw the problem to the list. Should we continue to fix each port individually? The usual reason to do so is so that we can send the patches upstream, but in many cases the software in question is old (i.e. in #37712 it's libxml version 1.x) and upstream will never update it.

We could possibly develop a bullet-proof reinplace that we could run in pre-configure on all configure.ac and configure.in files in the tarball. This could be placed in a portgroup which we could include in affected ports, or even better could be done by base automatically on all ports, if we get a new base version out soon. Usually I would not advocate this but I must admit it is tedious for both users and committers to have to do this one port at a time. If we are concerned that the reinplace is not bullet-proof and will cause problems, we could make it happen only when use_autoreconf or use_autoconf is yes, but there are several ports that manually run autoreconf without those keywords, so perhaps there could be a new keyword use_autoconf_1_13_fixes or something to allow ports to opt in even if use_auto(re)conf is not used.