i18n: extract strings with xgettext

The xgettext program knows about Python string formatting and will
mark messages with a special "#, python-format" comment in the hg.pot
file. When msgfmt compiles the file, it can check these messages to
ensure that the translated string uses the same conversion specifiers
as the original string.

The pygettext program is still used to extract the docstrings.

Makefile

@@ -1,88 +1,94 b''
 PREFIX=/usr/local
 export PREFIX
 PYTHON=python
 PURE=
 
 help:
 	@echo 'Commonly used make targets:'
 	@echo '  all          - build program and documentation'
 	@echo '  install      - install program and man pages to PREFIX ($(PREFIX))'
 	@echo '  install-home - install with setup.py install --home=HOME ($(HOME))'
 	@echo '  local        - build for inplace usage'
 	@echo '  tests        - run all tests in the automatic test suite'
 	@echo '  test-foo     - run only specified tests (e.g. test-merge1)'
 	@echo '  dist         - run all tests and create a source tarball in dist/'
 	@echo '  clean        - remove files created by other targets'
 	@echo '                 (except installed files or dist source tarball)'
 	@echo '  update-pot   - update i18n/hg.pot'
 	@echo
 	@echo 'Example for a system-wide installation under /usr/local:'
 	@echo '  make all && su -c "make install" && hg version'
 	@echo
 	@echo 'Example for a local installation (usable in this directory):'
 	@echo '  make local && ./hg version'
 
 all: build doc
 
 local:
 	$(PYTHON) setup.py $(PURE) build_py -c -d . build_ext -i build_mo
 	$(PYTHON) hg version
 
 build:
 	$(PYTHON) setup.py $(PURE) build
 
 doc:
 	$(MAKE) -C doc
 
 clean:
 	-$(PYTHON) setup.py clean --all # ignore errors of this command
 	find . -name '*.py[cdo]' -exec rm -f '{}' ';'
 	rm -f MANIFEST mercurial/__version__.py mercurial/*.so tests/*.err
 	$(MAKE) -C doc clean
 
 install: install-bin install-doc
 
 install-bin: build
 	$(PYTHON) setup.py $(PURE) install --prefix="$(PREFIX)" --force
 
 install-doc: doc
 	cd doc && $(MAKE) $(MFLAGS) install
 
 install-home: install-home-bin install-home-doc
 
 install-home-bin: build
 	$(PYTHON) setup.py $(PURE) install --home="$(HOME)" --force
 
 install-home-doc: doc
 	cd doc && $(MAKE) $(MFLAGS) PREFIX="$(HOME)" install
 
 MANIFEST-doc:
 	$(MAKE) -C doc MANIFEST
 
 MANIFEST: MANIFEST-doc
 	hg manifest > MANIFEST
 	echo mercurial/__version__.py >> MANIFEST
 	cat doc/MANIFEST >> MANIFEST
 
 dist:	tests dist-notests
 
 dist-notests:	doc MANIFEST
 	TAR_OPTIONS="--owner=root --group=root --mode=u+w,go-w,a+rX-s" $(PYTHON) setup.py -q sdist
 
 tests:
 	cd tests && $(PYTHON) run-tests.py $(TESTFLAGS)
 
 test-%:
 	cd tests && $(PYTHON) run-tests.py $(TESTFLAGS) $@
 
 update-pot:
 	mkdir -p i18n
-	pygettext -d doc -p i18n --docstrings \
-	mercurial/commands.py hgext/*.py hgext/*/__init__.py
-	pygettext -d all -p i18n mercurial hgext doc
-	msgcat --sort-by-file i18n/doc.pot i18n/all.pot > i18n/hg.pot
-	rm i18n/doc.pot i18n/all.pot
+	pygettext -d hg -p i18n --docstrings \
+	  mercurial/commands.py hgext/*.py hgext/*/__init__.py
+        # All strings marked for translation in Mercurial contain
+        # ASCII characters only. But some files contain string
+        # literals like this '\037\213'. xgettext thinks it has to
+        # parse these them even though they are not marked for
+        # translation. Extracting with an explicit encoding of
+        # ISO-8859-1 will make xgettext "parse" and ignore them.
+	find mercurial hgext doc -name '*.py' | xargs \
+	  xgettext --from-code ISO-8859-1 --join --sort-by-file \
+	  -d hg -p i18n -o hg.pot
 
 .PHONY: help all local build doc clean install install-bin install-doc \
 	install-home install-home-bin install-home-doc dist dist-notests tests \
 	update-pot