mingw32-git: Upgrade to v2.1.2

And use the new repository URL.

Signed-off-by: Thomas Braun <thomas.braun@byte-physics.de>
mingw32-git: Build and add the subtree documentation

Signed-off-by: Thomas Braun <thomas.braun@byte-physics.de>
Update package file

And also include the new dependency mingw32-libpcre.

Signed-off-by: Thomas Braun <thomas.braun@byte-physics.de>