Let us consider the example of Clang. ABI compatibility of Clang diverged from GCC5 and compiling things with Clang became quite a challenge in Ubuntu 16.04. At some point, a patch was committed and eventually merged to Clang 3.8.
Clang 3.8 is also available in Ubuntu repos, and when I add LLVM repo myself and update source list and try to install Clang-3.8, the version from Ubuntu repos gets installed as the latest (
apt is set to always prefer the highest version).
Without trying to compile code with it to see what happens, is there a good way to check if that patch is already in the Ubuntu repos or not?