Comment # 1 on bug 1174581 from Simon Lees

From the changelog:

Mon Sep 21 08:40:41 UTC 2015 - tchvatal@suse.com

- Remove CMAKE_INSTALL_LIBDIR declaration from the macros. rh#795542
  * It is unfortunate but SOME packages will now have to define it
    themselves because in some cases it is relative path while in
    others it is absolute one.

>From the RedHat bug:

Reading GNUInstallDirs.cmake convinces me that this bug in invalid.
CMAKE_INSTALL_LIBDIR isn't guaranteed to be relative, they just say you can use
it in the install() CMake command, which is true for both relative and absolute
path. And GNUInstallDirs.cmake defines CMAKE_INSTALL_FULL_LIBDIR variable which
is guaranteed to be absolute. So packages using
${CMAKE_INSTALL_PREFIX}/${CMAKE_INSTALL_LIBDIR} just need to be fixed and I see
no bug here in Fedora/CMake.

FWIW, Gentoo also defines CMAKE_INSTALL_LIBDIR to an absolute path. And Gentoo
being a source-based distribution would be especially vulnerable to problems
with packages assuming the path to be relative. And they handle it.


Having spoken to Fedora people they ended up dropping it altogether because
they decided it was too inconsistent. I don't have time to fix all the staging
issues from changing this or removing it atm. I believe someone submitted a SR
with a similar change several months back but it got reverted because it
changed too much.

I'll ask Tomas for more info seen as he tried it back then and he would be
responsible for finding the engineering manpower to fix the issues if we make
any changes here in the next few months.