KDE4 secret configuration variables

It seems that the main source of the configuration variables is in the CMake-files.
Especially kdelibs/cmake/modules/FindKDE4Internal.cmake.

Instead of the automake –sysconfdir, it seems you can use -DSYSCONF_INSTALL_DIR=/etc at least in kde. This does not seem to be CMake specific, but something kde4 has implemented in their build system.