Add release target to Makefile

Add simple helper target to automate basic release steps:
* version bump
* prepare release commit
* git commit, tag and sign

For library projects:
* update debian/changelog from TODO-RELEASE
* cleanup TODO-RELEASE

For non-library projects:
* update debian/changelog from git log

Note: it requires bumpversion package to be installed, debian/control is
adjusted accordingly. The helper itself is installed to facilitate reuse
by other libraries.

N. B: you still have to manually adjust LIBVERSION in previous commit -
see TODO-RELEASE header for details.

Use it as follows:
make REL=minor release

The REL parameter defines which component of the version [1] to bump and
can be any of { major, minor, patch }.

[1] http://semver.org/

Change-Id: I790ceb958195b9f6cbabfe8c977dc30e2bd7414b
Related: OS#1861

Makefile.am

@@ -7,13 +7,20 @@ pkgconfigdir = $(libdir)/pkgconfig
 pkgconfig_DATA = libosmocore.pc libosmocodec.pc libosmovty.pc libosmogsm.pc \
 		 libosmogb.pc libosmoctrl.pc libosmocoding.pc
 
+@RELMAKE@
+
+relengdir = $(includedir)
+releng_DATA = osmo-release.mk
+
+osmo-release.mk: git-version-gen
+
 BUILT_SOURCES = $(top_srcdir)/.version
 $(top_srcdir)/.version:
 	echo $(VERSION) > $@-t && mv $@-t $@
 dist-hook:
 	echo $(VERSION) > $(distdir)/.tarball-version
 
-EXTRA_DIST = git-version-gen .version README.md
+EXTRA_DIST = git-version-gen .version README.md osmo-release.mk
 
 if HAVE_DOXYGEN
 

configure.ac

@@ -11,6 +11,10 @@ AC_CONFIG_TESTDIR(tests)
 dnl kernel style compile messages
 m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
 
+dnl include release helper
+RELMAKE='-include osmo-release.mk'
+AC_SUBST([RELMAKE])
+
 dnl checks for programs
 AC_PROG_MAKE_SET
 AC_PROG_MKDIR_P

debian/control

@@ -281,6 +281,7 @@ Architecture: any
 Multi-Arch: same
 Section: libdevel
 Depends: libosmocore,
+         bumpversion,
          libtalloc-dev,
          ${misc:Depends}
 Description: Development headers for Open Source MObile COMmunications CORE library

osmo-release.mk

@@ -0,0 +1,28 @@
+ifdef REL
+NEW_VERSION := $(shell bumpversion --list --current-version $(VERSION) $(REL) --allow-dirty | awk -F '=' '{ print $$2 }')
+LIBVERS := $(shell git grep -n LIBVERSION | grep  '=' | grep am | grep -v LDFLAGS)
+ISODATE := $(shell date -I)
+endif
+
+release:
+ifeq ($(NEW_VERSION),)
+	@$(error Failed to determine NEW_VERSION - please fix versioning (current is $(VERSION)) before proceeding with the release)
+endif
+	@echo "Releasing" $(VERSION) "->" $(NEW_VERSION)"..."
+ifeq ($(LIBVERS),)
+	@gbp dch --debian-tag='%(version)s' --auto --meta --git-author --multimaint-merge
+else
+	@echo "You should NOT be doing this unless you've read and understood following article:"
+	@echo "https://www.gnu.org/software/libtool/manual/html_node/Updating-version-info.html#Updating-version-info"
+	@grep -v '#' TODO-RELEASE | sed 's/\t\+/:/g' | xargs -d'\n' -I entry dch -m -v $(NEW_VERSION) "entry"
+	@dch -r -m --distribution "unstable" ""
+	@grep '#' TODO-RELEASE > TODO-RELEASE.clean
+	@mv TODO-RELEASE.clean TODO-RELEASE
+	@echo "Do NOT push the release commit if you have not adjusted LIBVERSION in preceeding commit!!!"
+	@echo "Are you sure the following versions are correct?"
+	@echo $(LIBVERS)
+endif
+	@git add -u
+	@bumpversion --current-version $(VERSION) $(REL) --tag --commit --tag-name $(NEW_VERSION) --allow-dirty
+	@git tag -s $(NEW_VERSION) -f -m "Release v$(NEW_VERSION) on $(ISODATE)."
+	@echo "Release" $(NEW_VERSION) "prepared, tagged and signed."