CMake 3.5's pkg-config support broken

This is fallout from a post-beta merge of a new upstream version of cmake.

A feature freeze exception of a core build tool is altogether unreasonable. When it introduces regressions, it is unacceptable.

I have communicated to Michał and Gianfranco on IRC that if this issue is not resolved by my end of day, I intend to revert the merge, which clearly did not receive adequate testing.

Just confirming that the 3.5.0-1ubuntu2 upload doesn't help unfortunately.

Note cmake-extras needs to be rebuilt again (no-change) if cmake will get reverted (yes, we need to come up with some better packaging there - at least appropriately versioned dependencies on cmake).

hotfix for the bug.

the package is building on my ppa https://launchpad.net/~costamagnagianfranco/+archive/ubuntu/costamagnagianfranco-ppa

BTW I honestly think this was a typo in the set variable.
Probably a change like
+- _pkgconfig_set("${_pkg_check_modules_pkg}_${variable}" "${${_pkg_check_modules_pkg}_${variable}}")
++ _pkgconfig_set("${_pkg_check_prefix}_${variable}" "${${_pkg_check_prefix}_${variable}}")

is already enough.
Having them both results in something like:

GLIB2_INCLUDEDIR:INTERNAL=/usr/include
GLIB2_LIBDIR:INTERNAL=/usr/lib/x86_64-linux-gnu
GLIB2_PREFIX:INTERNAL=/usr

and

glib-2.0_INCLUDEDIR:INTERNAL=/usr/include
glib-2.0_LIBDIR:INTERNAL=/usr/lib/x86_64-linux-gnu
glib-2.0_PREFIX:INTERNAL=/usr

I think we could have just the former version.

Only variables started with the passed prefix (in this case `GLIB2`) should be set. I don't think the variables starting with `glib-2.0_` should be set.

yes, it was enough, and the patch was already upstreamed.
https://anonscm.debian.org/cgit/pkg-cmake/cmake.git/commit/?id=b71943bca4ed372568050d460960764ca2b3d4aa

The upstream code in the tarball for version 3.5.1 (https://cmake.org/files/v3.5/cmake-3.5.1.tar.gz) looks as follows:

foreach (variable IN ITEMS PREFIX INCLUDEDIR LIBDIR)
  _pkgconfig_set("${_pkg_check_prefix}_${variable}" "${${_pkg_check_prefix}_${variable}}")
endforeach ()

The fix was introduced upstream in https://cmake.org/gitweb?p=cmake.git;a=commitdiff;h=6f4f9054 and is mentioned in the last comment in this ticket: https://public.kitware.com/Bug/view.php?id=15903

Maybe this should be updated to use 3.5.1 which seems to have fixed that problem already?

please followup on https://bugs.launchpad.net/ubuntu/+source/cmake/+bug/1563580

This bug was fixed in the package cmake - 3.5.0-1ubuntu3

---------------
cmake (3.5.0-1ubuntu3) xenial; urgency=medium

  * Fix FindPkgModules.cmake (LP: #1563548)
    seems that a typo was preventing the correct internal variables from being set.

 -- Gianfranco Costamagna <email address hidden> Wed, 30 Mar 2016 00:19:04 +0200