Makefile: proper versioning of all crates in docs

Makefile

@@ -1,12 +1,34 @@
+DOCCRATES = arrayvec nodrop odds
 
-docs: VERSION
-	cargo doc
+# deps to delete the generated docs
+RMDOCS = unreachable void
+
+FEATURES = odds/unstable
+
+VERSIONS = $(patsubst %,target/VERS/%,$(DOCCRATES))
+
+docs: mkdocs subst $(RMDOCS)
+
+# https://www.gnu.org/software/make/manual/html_node/Automatic-Variables.html
+$(VERSIONS): Cargo.toml
+	mkdir -p $(@D)
+	cargo pkgid $(@F) | sed -e "s/.*#\(\|.*:\)//" > "$@"
+
+$(DOCCRATES): %: target/VERS/%
+	# Put in the crate version into the docs
+	find ./doc/$@ -name "*.html" -exec sed -i -e "s/<title>\(.*\) - Rust/<title>$@ $(shell cat $<) - \1 - Rust/g" {} \;
+
+subst: $(DOCCRATES)
+
+mkdocs: Cargo.toml
+	cargo doc --features=$(FEATURES)
 	rm -rf ./doc
 	cp -r ./target/doc ./doc
-	# Put in the crate version into the docs
-	find ./doc -name "*.html" -exec sed -i -e "s/<title>\(.*\) - Rust/<title>$(shell cat VERSION) - \1 - Rust/g" {} \;
+	-cat ./custom.css >> doc/main.css
 
-VERSION: Cargo.toml
-	cargo pkgid | sed -e "s/.*\/\(.*\)#\(.*\)/\1 - \2/" > $@
+$(RMDOCS): mkdocs
+	rm -r ./doc/$@
+	sed -i "/searchIndex\['$@'\]/d" doc/search-index.js
 
-.PHONY: docs
+
+.PHONY: docs mkdocs subst $(DOCCRATES) $(RMDOCS)