Fix the Autotools building

This applies a couple of fixes to the Autotools build system:

1. Revert !124 (merged). The LT_INIT macro is expanded by the ACX_USE_LIBTOOL_CONFIGURATION after the required monkey patches.
2. Add a dummy expansion of the LT_INIT macro to suppress the libtoolize warning.
3. Revert !116 (merged). First, CMakeLists.txt normally require more files to work correctly (e.g. the contents of the cmake directory). Second, the build systems are supposed to be fully independent and not know about each other. Those who want to build with CMake should not use the Autotools-generated release tarballs (i.e. the result of make dist). Instead, they should fetch the tarball directly from GitLab (for example cdi-2.5.1.1).