contrib: asdcplib: Apply a patch to fix compilation with latest Clang

The asdcplib code contains a C++ template which refers to member variables that doesn't exist. Earlier, this hasn't been an issue, as the C++ template never is instantiated, but current Clang versions (the upcoming 19.x version) diagnoses such issues already before the class is instantiated, leading to compilation errors on the asdcplib code.

This applies https://github.com/cinecert/asdcplib/pull/137 (which hasn't yet received any attention), fixing https://github.com/cinecert/asdcplib/issues/136.