As I understand it, the md5 checksums are generated for everything in %files at build time. These are used to do the foo -> .rpmsave/.rpmorig config file magic. I have a config file that I want to tailor to the installed machine's environment (eg putting in a line MYWEBROOT=http://`hostname`/top). But I also want that config file to be governed by the .rpmsave config file management magic. So maybe I'm misunderstanding the philosophy, but I want a directive that allows me to change the recorded md5 sum as part of the %post section. (Or an %attr directive that says to compute the md5 checksum for chosen files after %post completes.)
Best I can suggest is to add the directive %verify(nomd5) %config <your.conf> to turn off md5 verification of a locally modified file when verifying. The existing config file handling should (but you best check) save the previously installed (and locally modified) file when your package is upgraded with the above directives. Adding a directive to reset the md5 sum is not possible because there are 3 md5 sums involved in config file handling the file that is actually on the file system the file in the old package, already installed the file from the new package, about to be installed and added directives to handle the mishmosh would be complex at the minimum, and a possible security problem as well. Hope that helps.