Merge branch 'ct/autoconf-htmldir'

An earlier change to config.mak.autogen broke a build driven by the
./configure script when --htmldir is not specified on the command
line of ./configure.

* ct/autoconf-htmldir:
  Bugfix: undefined htmldir in config.mak.autogen

config.mak.in

@@ -8,6 +8,7 @@ LDFLAGS = @LDFLAGS@
 AR = @AR@
 TAR = @TAR@
 DIFF = @DIFF@
+PACKAGE_TARNAME = @PACKAGE_TARNAME@
 #INSTALL = @INSTALL@		# needs install-sh or install.sh in sources
 
 prefix = @prefix@
@@ -17,6 +18,7 @@ gitexecdir = @libexecdir@/git-core
 datarootdir = @datarootdir@
 template_dir = @datadir@/git-core/templates
 sysconfdir = @sysconfdir@
+docdir = @docdir@
 
 mandir = @mandir@
 htmldir = @htmldir@