endswith() leaves files out from subdirectories, which means projects
that add new subdirectories won't have those files included when they
probably should be.
* Root folder variable names are now more descriptive
* clone_repo() now restores the current working directory
* Removed setup_upstream_repo() since it's now identical to clone_repo()
* Moved am_patches()'s for loop into user scripts so the filename prefix
doesn't need to be included in every patch filename
* Renamed am_patches() to git_am() since its only job now is to run "git am"
* Removed unused apply_patches() function
* Fixed typo in git_am()'s ignore_whitespace arg name
This allows us to error out on deprecation warnings for thirdparty
libraries and standard library features.
Co-authored-by: Starlight220 <53231611+Starlight220@users.noreply.github.com>
