build: pre-process vim patches with uncrustify

This will enable a larger amount of chunks being automatically included
due to fewer formatting differences between the vim and neovim files.

The strategy is straightforward, if a bit tedious:

- Get a list of all changed files.
- Checkout parent commit. Copy all relevant files to a temporary
  location.
- Checkout patch commit. Copy all relevant files to a temporary
  location.
- Format .c and .h files with uncrustify.
- Generate a diff from from these files.

Closes #6226

scripts/vim-patch.sh

@@ -279,6 +279,37 @@ preprocess_patch() {
  "$file" > "$file".tmp && mv "$file".tmp "$file"
 }
 
+uncrustify_patch() {
+ local commit="$1"
+ local changed_files=()
+ while IFS='' read -r file; do changed_files+=("$file"); done < <(git diff-tree --name-only --no-commit-id -r "${commit}")
+
+ local patch_path=$NVIM_SOURCE_DIR/build/vim_patch
+ rm -rf "$patch_path"
+ mkdir -p "$patch_path"/{before,after,patch}
+
+ git checkout --quiet "$commit"~
+ cp "${changed_files[@]}" "$patch_path"/before
+
+ git checkout --quiet "$commit"
+ cp "${changed_files[@]}" "$patch_path"/after
+
+ uncrustify -c "$NVIM_SOURCE_DIR"/src/uncrustify.cfg -q --replace --no-backup "$patch_path"/{before,after}/*.[ch]
+
+ for file in "${changed_files[@]}"; do
+ local basename
+ basename=$(basename "$file")
+ local before=$patch_path/before/$basename
+ local after=$patch_path/after/$basename
+ local patchfile="$patch_path"/patch/"$basename".patch
+ git diff --no-index --patch "$before" "$after" > "$patchfile"
+ sed -E "s|$before|/$file|g" -i "$patchfile"
+ sed -E "s|$after|/$file|g" -i "$patchfile"
+ done
+
+ cat "$patch_path"/patch/*.patch
+}
+
 get_vimpatch() {
  get_vim_sources
 
@@ -287,7 +318,12 @@ get_vimpatch() {
  msg_ok "Found Vim revision '${vim_commit}'."
 
  local patch_content
- patch_content="$(git --no-pager show --unified=5 --color=never -1 --pretty=medium "${vim_commit}")"
+ if check_executable uncrustify; then
+ patch_content="$(uncrustify_patch "${vim_commit}")"
+ git switch --quiet master
+ else
+ patch_content="$(git --no-pager show --unified=5 --color=never -1 --pretty=medium "${vim_commit}")"
+ fi
 
  cd "${NVIM_SOURCE_DIR}"