* MASTER_SITES variable can now look like MACRO1/subdir1 MACRO2/subdir2, and
be expanded in a way that you expect it to, that is apply different subdirs
to different sites. You can safely replace ${M_S_FOO:S/%SUBDIR%/bar/} with
FOO/bar.
* If M_S_SUBDIR is unset, a macro in M_S won't set it anymore, but rather
substitute %SUBDIR% all by itself. Now it's possible to use macros with
different default subdirs and they will expand in a proper way.
aa5fbade3d