make: alter how we compute compiler flags for setup.py

This is portable between BSD and GNU make. I'm not thrilled with how
it worked out, but it's portable and solves the problem.

Makefile

@@ -1,235 +1,239
 # If you want to change PREFIX, do not just edit it below. The changed
 # value wont get passed on to recursive make calls. You should instead
 # override the variable on the command like:
 #
 # % make PREFIX=/opt/ install
 
 PREFIX=/usr/local
 export PREFIX
 PYTHON=python
 $(eval HGROOT := $(shell pwd))
 HGPYTHONS ?= $(HGROOT)/build/pythons
 PURE=
 PYFILES:=$(shell find mercurial hgext doc -name '*.py')
 DOCFILES=mercurial/help/*.txt
 export LANGUAGE=C
 export LC_ALL=C
 TESTFLAGS ?= $(shell echo $$HGTESTFLAGS)
 
 # Set this to e.g. "mingw32" to use a non-default compiler.
 COMPILER=
 
+COMPILERFLAG_tmp_ =
+COMPILERFLAG_tmp_${COMPILER} ?= -c $(COMPILER)
+COMPILERFLAG=${COMPILERFLAG_tmp_${COMPILER}}
+
 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.t)'
 	@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 $(COMPILER:%=-c %) -i \
-	  build_hgexe $(COMPILER:%=-c %) -i \
+	  build_ext $(COMPILERFLAG) -i \
+	  build_hgexe $(COMPILERFLAG) -i \
 	  build_mo
 	env HGRCPATH= $(PYTHON) hg version
 
 build:
-	$(PYTHON) setup.py $(PURE) build $(COMPILER:%=-c %)
+	$(PYTHON) setup.py $(PURE) build $(COMPILERFLAG)
 
 wheel:
-	FORCE_SETUPTOOLS=1 $(PYTHON) setup.py $(PURE) bdist_wheel $(COMPILER:%=-c %)
+	FORCE_SETUPTOOLS=1 $(PYTHON) setup.py $(PURE) bdist_wheel $(COMPILERFLAG)
 
 doc:
 	$(MAKE) -C doc
 
 clean:
 	-$(PYTHON) setup.py clean --all # ignore errors from this command
 	find contrib doc hgext hgext3rd i18n mercurial tests \
 		\( -name '*.py[cdo]' -o -name '*.so' \) -exec rm -f '{}' ';'
 	rm -f $(addprefix mercurial/,$(notdir $(wildcard mercurial/pure/[a-z]*.py)))
 	rm -f MANIFEST MANIFEST.in hgext/__index__.py tests/*.err
 	rm -f mercurial/__modulepolicy__.py
 	if test -d .hg; then rm -f mercurial/__version__.py; fi
 	rm -rf build packages mercurial/locale
 	$(MAKE) -C doc clean
 	$(MAKE) -C contrib/chg distclean
 
 install: install-bin install-doc
 
 install-bin: build
 	$(PYTHON) setup.py $(PURE) install --root="$(DESTDIR)/" --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)" --prefix="" --force
 
 install-home-doc: doc
 	cd doc && $(MAKE) $(MFLAGS) PREFIX="$(HOME)" install
 
 MANIFEST-doc:
 	$(MAKE) -C doc MANIFEST
 
 MANIFEST.in: MANIFEST-doc
 	hg manifest | sed -e 's/^/include /' > MANIFEST.in
 	echo include mercurial/__version__.py >> MANIFEST.in
 	sed -e 's/^/include /' < doc/MANIFEST >> MANIFEST.in
 
 dist:	tests dist-notests
 
 dist-notests:	doc MANIFEST.in
 	TAR_OPTIONS="--owner=root --group=root --mode=u+w,go-w,a+rX-s" $(PYTHON) setup.py -q sdist
 
 check: tests
 
 tests:
 	cd tests && $(PYTHON) run-tests.py $(TESTFLAGS)
 
 test-%:
 	cd tests && $(PYTHON) run-tests.py $(TESTFLAGS) $@
 
 testpy-%:
 	@echo Looking for Python $* in $(HGPYTHONS)
 	[ -e $(HGPYTHONS)/$*/bin/python ] || ( \
 	cd $$(mktemp --directory --tmpdir) && \
         $(MAKE) -f $(HGROOT)/contrib/Makefile.python PYTHONVER=$* PREFIX=$(HGPYTHONS)/$* python )
 	cd tests && $(HGPYTHONS)/$*/bin/python run-tests.py $(TESTFLAGS)
 
 check-code:
 	hg manifest | xargs python contrib/check-code.py
 
 update-pot: i18n/hg.pot
 
 i18n/hg.pot: $(PYFILES) $(DOCFILES) i18n/posplit i18n/hggettext
 	$(PYTHON) i18n/hggettext mercurial/commands.py \
 	  hgext/*.py hgext/*/__init__.py \
 	  mercurial/fileset.py mercurial/revset.py \
 	  mercurial/templatefilters.py mercurial/templatekw.py \
 	  mercurial/templater.py \
 	  mercurial/filemerge.py \
 	  mercurial/hgweb/webcommands.py \
 	  $(DOCFILES) > i18n/hg.pot.tmp
         # 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 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.
 	echo $(PYFILES) | xargs \
 	  xgettext --package-name "Mercurial" \
 	  --msgid-bugs-address "<[e-mail]>" \
 	  --copyright-holder "Matt Mackall <[e-mail]> and others" \
 	  --from-code ISO-8859-1 --join --sort-by-file --add-comments=i18n: \
 	  -d hg -p i18n -o hg.pot.tmp
 	$(PYTHON) i18n/posplit i18n/hg.pot.tmp
         # The target file is not created before the last step. So it never is in
         # an intermediate state.
 	mv -f i18n/hg.pot.tmp i18n/hg.pot
 
 %.po: i18n/hg.pot
         # work on a temporary copy for never having a half completed target
 	cp $@ $@.tmp
 	msgmerge --no-location --update $@.tmp $^
 	mv -f $@.tmp $@
 
 # Packaging targets
 
 osx:
 	python -c 'import bdist_mpkg.script_bdist_mpkg' || \
 	   (echo "Missing bdist_mpkg (easy_install bdist_mpkg)"; false)
 	rm -rf dist/mercurial-*.mpkg
 	python -m bdist_mpkg.script_bdist_mpkg setup.py --
 	python contrib/fixpax.py dist/mercurial-*.mpkg/Contents/Packages/*.pkg/Contents/Archive.pax.gz
 	mkdir -p packages/osx
 	N=`cd dist && echo mercurial-*.mpkg | sed 's,\.mpkg$$,,'` && hdiutil create -srcfolder dist/$$N.mpkg/ -scrub -volname "$$N" -ov packages/osx/$$N.dmg
 	rm -rf dist/mercurial-*.mpkg
 
 deb:
 	contrib/builddeb
 
 ppa:
 	contrib/builddeb --source-only
 
 docker-debian-jessie:
 	mkdir -p packages/debian-jessie
 	contrib/dockerdeb debian jessie
 
 docker-ubuntu-trusty:
 	mkdir -p packages/ubuntu-trusty
 	contrib/dockerdeb ubuntu trusty
 
 fedora20:
 	mkdir -p packages/fedora20
 	contrib/buildrpm
 	cp rpmbuild/RPMS/*/* packages/fedora20
 	cp rpmbuild/SRPMS/* packages/fedora20
 	rm -rf rpmbuild
 
 docker-fedora20:
 	mkdir -p packages/fedora20
 	contrib/dockerrpm fedora20
 
 fedora21:
 	mkdir -p packages/fedora21
 	contrib/buildrpm
 	cp rpmbuild/RPMS/*/* packages/fedora21
 	cp rpmbuild/SRPMS/* packages/fedora21
 	rm -rf rpmbuild
 
 docker-fedora21:
 	mkdir -p packages/fedora21
 	contrib/dockerrpm fedora21
 
 centos5:
 	mkdir -p packages/centos5
 	contrib/buildrpm --withpython
 	cp rpmbuild/RPMS/*/* packages/centos5
 	cp rpmbuild/SRPMS/* packages/centos5
 
 docker-centos5:
 	mkdir -p packages/centos5
 	contrib/dockerrpm centos5 --withpython
 
 centos6:
 	mkdir -p packages/centos6
 	contrib/buildrpm
 	cp rpmbuild/RPMS/*/* packages/centos6
 	cp rpmbuild/SRPMS/* packages/centos6
 
 docker-centos6:
 	mkdir -p packages/centos6
 	contrib/dockerrpm centos6
 
 centos7:
 	mkdir -p packages/centos7
 	contrib/buildrpm
 	cp rpmbuild/RPMS/*/* packages/centos7
 	cp rpmbuild/SRPMS/* packages/centos7
 
 docker-centos7:
 	mkdir -p packages/centos7
 	contrib/dockerrpm centos7
 
 .PHONY: help all local build doc clean install install-bin install-doc \
 	install-home install-home-bin install-home-doc \
 	dist dist-notests check tests check-code update-pot \
 	osx fedora20 docker-fedora20 fedora21 docker-fedora21 \
 	centos5 docker-centos5 centos6 docker-centos6 centos7 docker-centos7