Implement catchup targets

Implement a new target 'catchup' that will backport upstream commits
from the current package version to HEAD.
Implement a new target 'catchup-<commit|tag>' that will backport
upstream commits up to the target, as resolvable by git. This powers
'catchup'.
Rework the target 'backport-<commit>' to clone and use the upstream
git repository instead of using GitHub URLs. This also simplifies the
resolution of targets to full commit hashes, as needed to ensure unique
patch names and entries in 'series'.

'make catchup' will backport all the patches to catch this package up to
the upstream's HEAD
'make catchup-v5.0' will backport all the patches to catch this package
up to tag "v5.0" upstream.
'make catchup-ffdcba' will backport all the patches between this
package's current version and the upstream commit ffdcba.
'make backport-ffdcba' will backport ONLY upstream commit ffdcba.

All targets will produce patches named "backport-<commit>.patch", where
<commit> is the full SHA1 commit hash, regardless of whether you used an
abbreviated hash (or a tag, for catchup-%).

Patches are added to 'series' in chronological order, unless they're
already anywhere in that file.

Author: bwarden

Makefile.common

@@ -582,27 +582,68 @@ cloc: $(SRPMFILE)
 	@$(MOCK) --clean --scrub=chroot --uniqueext=$(PKG_NAME)
 	cat results/cloc.txt
 
+#help catchup: Backport the commits from the current version to the upstream HEAD (not release).
+#help Only works if giturl is defined and the current package version can be mapped to a git tag.
+catchup:
+	$(MAKE) catchup-HEAD
+
+#help catchup-<commit|tag>: Backport the commits from the current version to the specified commit or tag.
+#help Only works if giturl is defined and the current package version can be mapped to a git tag.
+catchup-%:
+	@target=$*; \
+	giturl=$$(grep -E '^giturl\s*=\s*\S+' options.conf | sed 's/giturl\s*=\s*//' 2>/dev/null); \
+	if [[ -z "$${giturl}" ]]; then \
+		echo "Error: giturl not defined in options.conf"; \
+		exit 1; \
+	fi; \
+	mkdir -p results; \
+	if [[ -d results/$(PKG_NAME) ]]; then \
+		echo "Reusing existing repository..."; \
+		git -C results/$(PKG_NAME) fetch origin; \
+	else \
+		echo "Cloning upstream repository..."; \
+		git -C results clone "$${giturl}" $(PKG_NAME); \
+	fi; \
+	if ! git -C results/$(PKG_NAME) rev-parse --verify --quiet "$${target}" >/dev/null; then \
+		echo "Error: Target commit/tag $${target} not found"; \
+		exit 1; \
+	fi; \
+	echo "Version: $$(rpm -q --qf '%{VERSION}\n' --specfile $(SPECFILE) | head -1)"; \
+	current_tag=$$(git -C results/$(PKG_NAME) tag --list | grep -E "^($(PKG_NAME)-)?v?$$(rpm -q --qf '%{VERSION}\n' --specfile $(SPECFILE) | head -1)$$") || { \
+		echo "Error: No tag found for current package version"; \
+		exit 1; \
+	}; \
+	echo "Catching up from $${current_tag} to $${target}"; \
+	for commit in $$(git -C results/$(PKG_NAME) log --reverse --pretty=oneline $${current_tag}..$${target} | cut -d' ' -f1); do \
+		$(MAKE) backport-$${commit}; \
+	done;
+
+
 #help backport-<commit>: Retrieve a commit from the upstream git repository and save it as a backport patch.
-#help Currently only works with GitHub repositories. The giturl is read from options.conf.
+#help The giturl is read from options.conf.
 backport-%:
 	@commit=$*; \
 	echo "Backporting commit: $${commit}"; \
-	giturl=$$(grep -E '^giturl\s*=\s*https://github.com' options.conf | sed 's/giturl\s*=\s*//' | sed 's/\.git$$//' | sed 's/\/$$//' 2>/dev/null); \
+	giturl=$$(grep -E '^giturl\s*=\s*\S+' options.conf | sed 's/giturl\s*=\s*//' 2>/dev/null); \
 	if [[ -z "$${giturl}" ]]; then \
 		echo "Error: giturl not defined in options.conf"; \
 		exit 1; \
 	fi; \
-	if ! curl -s -L -o $@.patch $${giturl}/commit/$*.patch || [[ "Not Found" == $$(< $@.patch) ]]; then \
-		rm -f $@.patch; \
-		echo "Error: Failed to download commit $*"; \
-		exit 1; \
+	mkdir -p results; \
+	if [[ -d results/$(PKG_NAME) ]]; then \
+		echo "Reusing existing repository..."; \
+		git -C results/$(PKG_NAME) fetch origin; \
+	else \
+		echo "Cloning upstream repository..."; \
+		git -C results clone "$${giturl}" $(PKG_NAME); \
 	fi; \
-	patch=$@.patch; \
-	full_commit=$$(head -1 $@.patch | grep -oE '\b$*\S+' 2>/dev/null); \
-	if ! [[ -z "$${full_commit}" ]]; then \
-		patch=backport-$${full_commit}.patch; \
-		mv $@.patch $${patch}; \
+	full_commit=$$(git -C results/$(PKG_NAME) show --pretty=oneline $${commit} 2>/dev/null | head -1 | cut -d' ' -f 1); \
+	if [[ -z "$${full_commit}" ]]; then \
+		echo "Error: Commit for $${commit} not found"; \
+		exit 1; \
 	fi; \
+	patch=backport-$${full_commit}.patch; \
+	git -C results/$(PKG_NAME) format-patch -1 --stdout $${full_commit} > $${patch}; \
 	if [[ -s $${patch} ]]; then \
 		echo "$${patch} created"; \
 		grep -qE "^$${patch}$$" series 2>/dev/null || echo "$${patch}" >> series; \