allow installation of man and html doc from the man and html branches

This patch introduces a make target "quick-install-html" which installs
the html documentation from the branch origin/html, without the need for
asciidoc/xmlto. This is analogous to the existing "quick-install-doc"
target for the man pages.

We advertise these targets in the INSTALL file now.

Signed-off-by: Michael J Gruber <michaeljgruber+gmane@fastmail.fm>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/Makefile b/Documentation/Makefile
index 62269e3..ded0e40 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -44,6 +44,7 @@
 INSTALL?=install
 RM ?= rm -f
 DOC_REF = origin/man
+HTML_REF = origin/html
 
 infodir?=$(prefix)/share/info
 MAKEINFO=makeinfo
@@ -222,4 +223,7 @@
 quick-install:
 	sh ./install-doc-quick.sh $(DOC_REF) $(DESTDIR)$(mandir)
 
+quick-install-html:
+	sh ./install-doc-quick.sh $(HTML_REF) $(DESTDIR)$(htmldir)
+
 .PHONY: .FORCE-GIT-VERSION-FILE
diff --git a/INSTALL b/INSTALL
index 2bae53f..15462e9 100644
--- a/INSTALL
+++ b/INSTALL
@@ -117,6 +117,12 @@
 
 	http://www.kernel.org/pub/software/scm/git/docs/
 
+   There are also "make quick-install-doc" and "make quick-install-html"
+   which install preformatted man pages and html documentation.
+   This does not require asciidoc/xmlto, but it only works from within
+   a cloned checkout of git.git with these two extra branches, and will
+   not work for the maintainer for obvious chicken-and-egg reasons.
+
    It has been reported that docbook-xsl version 1.72 and 1.73 are
    buggy; 1.72 misformats manual pages for callouts, and 1.73 needs
    the patch in contrib/patches/docbook-xsl-manpages-charmap.patch
diff --git a/Makefile b/Makefile
index cf320cd..857bc09 100644
--- a/Makefile
+++ b/Makefile
@@ -1403,6 +1403,9 @@
 quick-install-doc:
 	$(MAKE) -C Documentation quick-install
 
+quick-install-html:
+	$(MAKE) -C Documentation quick-install-html
+
 
 
 ### Maintainer's dist rules