Subject: cmake-build-system should set CMAKE_INSTALL_LIBDIR and CMAKE_PREFIX_PATH

From: 宋文武 <[email-masked]>
Date: Sun, 02 Nov 2014 21:24:01 +0800

if CMAKE_INSTALL_LIBDIR not set to `lib`, GNUInstallDirs.cmake will install
libraries files to $out/lib64.

if CMAKE_PREFIX_PATH not set to PATH of `inputs`, cmake will unable to
find cmake modules of inputs.

I find this when packaging https://github.com/lxdg/libqtxdg.