Add --with-apache2-httpd option so users can override apxs's notion of where the httpd executable is. XSBuilder's header parser runs from buildconf now instead of configure, so we will include those tables in the release tarball. buildconf gets an additional --with-perl option for running the xsbuilder.pl parsing script. The XS generation code in xsbuilder.pl has moved to glue/perl/Makefile.PL.
Notes: This patch probably breaks the Win32 build, and the new arg parsing code for buildconf is copied from httpd's buildconf script.