patches: Patch the llvm 12.x release to include support for std::filesystem in libcxx

Dockerfile

@@ -39,6 +39,7 @@ COPY wrappers/uasm-wrapper.sh $TOOLCHAIN_PREFIX/bin
 # Build everything that uses the llvm monorepo. We need to build the mingw runtime before the compiler-rt/libunwind/libcxxabi/libcxx runtimes.
 COPY build-llvm.sh strip-llvm.sh install-wrappers.sh build-mingw-w64.sh build-mingw-w64-tools.sh build-compiler-rt.sh build-mingw-w64-libraries.sh build-libcxx.sh build-openmp.sh ./
 COPY wrappers/*.sh wrappers/*.c wrappers/*.h ./wrappers/
+COPY patches/llvm-project/*.patch ./patches/llvm-project/
 RUN ./build-llvm.sh $TOOLCHAIN_PREFIX && \
     ./strip-llvm.sh $TOOLCHAIN_PREFIX && \
     ./install-wrappers.sh $TOOLCHAIN_PREFIX && \