Split NEWS into per-release doc/en/release-notes/bzr-*.txt

.bzrignore

@@ -19,7 +19,7 @@ bzr.1
 ./doc/**/*.html
 ./doc/developers/performance.png
 ./doc/en/user-reference/*.txt
-./doc/en/release-notes/*.txt
+./doc/en/release-notes/index.txt
 BRANCH-INFO
 # setup.py working directory
 ./build

Makefile

@@ -139,11 +139,13 @@ SPHINX_DEPENDENCIES = \
 	doc/developers/Makefile \
 	doc/developers/make.bat
 
+NEWS_FILES = $(wildcard doc/en/release-notes/bzr-*.txt)
+
 doc/en/user-reference/index.txt: $(MAN_DEPENDENCIES)
 	$(PYTHON) tools/generate_docs.py -o $@ rstx
 
-doc/en/release-notes/index.txt: NEWS tools/generate_release_notes.py
-	$(PYTHON) tools/generate_release_notes.py NEWS $@
+doc/en/release-notes/index.txt: $(NEWS_FILES) tools/generate_release_notes.py
+	$(PYTHON) tools/generate_release_notes.py $@ $(NEWS_FILES)
 
 doc/%/Makefile: doc/en/Makefile
 	$(PYTHON) -c "import shutil; shutil.copyfile('$<', '$@')"