Add support for hlint

Makefile

@@ -1,4 +1,4 @@
-.PHONY: default all install watch clean build release distclean
+.PHONY: default all install watch clean build release distclean lint
 default: all
 
 all: build
@@ -6,30 +6,34 @@ all: build
 build: builddir build/bin/annotator
 
 GHCFLAGS = -iapp -isrc -Wall -O2 -outputdir build/.obj
+BUILDDIR = build
 DESTDIR = ~/.local
 BINDIR = ${DESTDIR}/bin
 DOCDIR = ${DESTDIR}/share/doc/annotator
 
 builddir:
-	mkdir -p build/bin build/.obj
+	mkdir -p $(BUILDDIR)/bin $(BUILDDIR)/.obj $(BUILDDIR)/ci $(BUILDDIR)/dist
 
-build/bin/annotator: app/Main.hs src/*.hs
+$(BUILDDIR)/bin/annotator: app/Main.hs src/*.hs
 	ghc --make $(GHCFLAGS) $< -o $@
 
 watch:
 	@git ls-files src app Makefile | entr make -s build install
 
+lint:
+	@-hlint -g --cc > $(BUILDDIR)/ci/hlint.report.json
+
 clean:
-	@rm -rf build
+	@rm -rf $(BUILDDIR)
 	@find . -name "*.hi" -delete
 	@find . -name "*.fix" -delete
 
 distclean: clean
 	@rm -rf dist
 
-install: build/bin/annotator
-	@install -D -t ${BINDIR} $<
-	@install -D -t ${DOCDIR} README.md
+install: $(BUILDDIR)/bin/annotator
+	@install -m 0755 -D -t ${BINDIR} $<
+	@install -m 0644 -D -t ${DOCDIR} README.md
 
 release: script/make-release
 	@$<