Backporting and forward porting on APR / APR-UTIL

[Rainer Jung]

I'm a bit undecided whether to port some changes between APR and 
APR-UTIL branches:

- r780882 (wrowe): fix vpath building for xml/expat (removing 
"configure" target in Makefile.in)
  The change is in the 1.3.x branch, but neither in any older nor newer 
branches.

- r979102 (rjung): Updating buildconf.sh and configure.in for in 
xml/expat to allow building with libtool 2. Applied to 1.5, 1.4 and 1.3. 
Should I backport to older branches, or do we want to stay very 
conservatve here? I'd say backport, because otherwise we might run into 
the same problem we had with the first tarball for 2.2.16 again, namely 
that the machine of the RM is to modern, even when preparing e.g. an 
httpd 2.0 release.

- r979109 (rjung): Updating config.guess and config.sub to allow for 
better detection of modern platforms. Applied to APR 1.3, ..., trunk and 
apr-util 1.3, ..., 1.5. I suggest applying to the old branches as well.

Regards,

Rainer