mingw32-gnugp: Fix some formatting issues

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>
mingw32-gnupg: Add the missing dependency to libiconv

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>
mingw32-gnupg: Add a patch to use the correct iconv DLL name

Signed-off-by: Sebastian Schuberth <sschuberth@gmail.com>