* Makefile.in: Define the update-changes target to merge the change files from the changes directory to the top of the CHANGES file and remove them afterwards. If a Subversion binary was found during configure try to svn rm them otherwise just delete them.
* configure.in: Search for the Subversion binary.
* acinclude.m4: Set the corresponding Makefile variable for the Subversion binary.
* README.CHANGES: New file to document the new approach.
Can we have mercy with people working on case-preserving file systems?
Consider case insensitive filessystems
Consider case insensitive filessystems and thus choose a new non conflicting name for the directory to store CHANGES entries.