dev-lang/php: add php-7.1.0 in the new "7.1" slot.

dev-lang/php: add php-7.1.0 in the new "7.1" slot.

This is a new upstream release and the ebuild incorporates a few fixes
facilitated by upstream changes:

  1. We use app-text/tidy-html5 instead of the abandoned app-text/htmltidy.

  2. Upstream now detects heimdal correctly so our workaround has been
     removed.

  3. The custom Gentoo branding that required us to rebuild all of the
     autotools files has been removed. A few build dependencies were
     eliminated as a result, and the autotools and libtool eclasses were
     dropped.

The changes above have associated Gentoo bugs. In addition, the hack
for bug 343481 was removed, since it had no effect on the configure
script for v7.1.0. I do not know if the fix is simply no longer
needed, or if it should be forward-ported.

Gentoo-Bug: 585474
Gentoo-Bug: 597448
Gentoo-Bug: 597450

Package-Manager: portage-2.3.0