- move headers directly to $out/include and set up symlinks. Some packages were failing to find them (e.g. mariadb). - postInstall was failing, only it was ignored due to a bug; now it succeeds.
- move headers directly to $out/include and set up symlinks. Some packages were failing to find them (e.g. mariadb). - postInstall was failing, only it was ignored due to a bug; now it succeeds.