The devtools/README file shows directories as defaults that do not
contain ending slashes. Ie, confLIBDIR shows default of '/usr/lib'.
Assuming that confLIBDIR does not require an ending slash, setting that variable to a value such as '/usr/local/lib' and using shared library building, 'Build install' creates /usr/local/liblibdkim.so, which is not what was desired. Adding a final slash to the config variable fixes the problem. Either this should be documented or fixed :)