As a diff or patch file is preferred as is typical any where.
diff -uN file file.new > Reason.patch
so in your case something like below with the zm version that the patch is for.
diff -uN zm_remote_camera_http.cpp.orig zm_remote_camera_http.cpp > zm_remote_camera_http.cpp_ZM-1.24.1.patch
Just remember to disable HTML in the post so that it don't strip anything out.