msys-core: Remove the old text files that explain skipped patches

In the same run, rename the patch files in use to be numbered
consecutively.
msys-core: increment build number to prevent name clash

Using the exact same name as the original MSYS package prevents rebuilding,
because the 'package' step overwrites the downloaded source package.

Signed-off-by: Karsten Blees <blees@dcon.de>
msys-core: stat/lstat: drop sub-directory counting for directories

Add a patch that removes extra counting of sub-directories in [l]stat.
This fixes stat.st_nlink for directories (always 1) and improves [l]stat
performance by at least factor 2 (for empty dirs, factor 10 for dirs with
~500 entries).

Note: programs that _rely_ on st_nlink being the number of sub-dirs + 2
need to be fixed.

Signed-off-by: Karsten Blees <blees@dcon.de>
msys-core: fix parallel make (MinGW bug #1950 [1])

[1] http://sourceforge.net/p/mingw/bugs/1950

Signed-off-by: Karsten Blees <blees@dcon.de>