dpatch - 2.0.41 main

dpatch is an easy to use patch system for Debian packages, somewhat
similar to the dbs package, but much simpler to use.
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It lets you store patches and other simple customization templates in
debian/patches and otherwise does not require much reorganization of
your source tree. To get the patches applied at build time you simply
need to include a makefile snippet and then depend on the
patch/unpatch target in the build or clean stage of debian/rules - or
you can use the dpatch patching script directly.
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It can easily apply patches only on specific architectures if needed.