[waffle] [PATCH] revert commit 92116dae to make it build with cmake < 2.8.12

[Matej Cepl]

Hi,

when trying to build waffle 1.4.2 on RHEL-7 with cmake-2.8.11 the build
fails when trying to link against -lPRIVATE. I believe that the cause of
this is https://github.com/waffle-gl/waffle/commit/92116dae which is
incompatible with cmake < 2.8.12 (certainly present on RHEL-7 and
I don’t think we will upgrade it any time soon). When I have patched out
this commit with the attached patch, the build succeeded. So this patch
will be now part of the Fedora/RHEL packages from now on, I guess.

Anyway, I would suggest either to revert the commit 92116dae or (at
least) to bump the variable cmake_minimum_required to at least 2.8.12.

What do you think?

Best,

Matěj