Merge branch 'jk/subtree-install-fix' into maint

We did not generate HTML version of documentation to "git subtree"
in contrib/.

* jk/subtree-install-fix:
  subtree: add makefile target for html docs

contrib/subtree/Makefile

@@ -21,13 +21,14 @@ GIT_SUBTREE    := git-subtree
 GIT_SUBTREE_DOC := git-subtree.1
 GIT_SUBTREE_XML := git-subtree.xml
 GIT_SUBTREE_TXT := git-subtree.txt
+GIT_SUBTREE_HTML := git-subtree.html
 
 all: $(GIT_SUBTREE)
 
 $(GIT_SUBTREE): $(GIT_SUBTREE_SH)
 	cp $< $@ && chmod +x $@
 
-doc: $(GIT_SUBTREE_DOC)
+doc: $(GIT_SUBTREE_DOC) $(GIT_SUBTREE_HTML)
 
 install: $(GIT_SUBTREE)
 	$(INSTALL) -d -m 755 $(DESTDIR)$(libexecdir)
@@ -46,6 +47,10 @@ $(GIT_SUBTREE_XML): $(GIT_SUBTREE_TXT)
 	asciidoc -b docbook -d manpage -f $(ASCIIDOC_CONF) \
 		-agit_version=$(gitver) $^
 
+$(GIT_SUBTREE_HTML): $(GIT_SUBTREE_TXT)
+	asciidoc -b xhtml11 -d manpage -f $(ASCIIDOC_CONF) \
+		-agit_version=$(gitver) $^
+
 test:
 	$(MAKE) -C t/ test