[PATCH] Allow generating a non-default set of documentation

[Junio C Hamano <gitster@pobox.com>]

By default, "make doc" generates the manpages and htmldocs in the
Documentation directory, but you may want to change this depending
on the target environment, e.g. to include 'pdf'.  Introduce a new
Makefile variable DEFAULT_DOC_TARGET to allow customizing this.

The primary motivation is to let us check documentation patches with

    $ DEFAULT_DOC_TARGET=git-push.1 make doc

but it is not so far-fetched to imagine that Windows users may want to
omit manpages with

    $ DEFAULT_DOC_TARGET=html make doc

or somesuch; this lets interested people to enhance the install-doc
target in a similar way.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

 Makefile | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git c/Makefile w/Makefile
index 8413606..250b87a 100644
--- c/Makefile
+++ w/Makefile
@@ -299,6 +299,12 @@ all::
 #   DEFAULT_EDITOR='$GIT_FALLBACK_EDITOR',
 #   DEFAULT_EDITOR='"C:\Program Files\Vim\gvim.exe" --nofork'
 #
+# You can define DEFAULT_DOC_TARGET to something other than "all" to change it
+# from the built-in default of generating manpages and htmldocs.  e.g.
+#
+#   DEFAULT_DOC_TARGET='man html info pdf'
+#   DEFAULT_DOC_TARGET='html'
+#
 # Define COMPUTE_HEADER_DEPENDENCIES to "yes" if you want dependencies on
 # header files to be automatically computed, to avoid rebuilding objects when
 # an unrelated header file changes.  Define it to "no" to use the hard-coded
@@ -1496,6 +1502,8 @@ ifneq (,$(SOCKLEN_T))
 	BASIC_CFLAGS += -Dsocklen_t=$(SOCKLEN_T)
 endif
 
+DEFAULT_DOC_TARGET ?= all
+
 ifeq ($(uname_S),Darwin)
 	ifndef NO_FINK
 		ifeq ($(shell test -d /sw/lib && echo y),y)
@@ -2468,10 +2476,10 @@ $(XDIFF_LIB): $(XDIFF_OBJS)
 $(VCSSVN_LIB): $(VCSSVN_OBJS)
 	$(QUIET_AR)$(RM) $@ && $(AR) rcs $@ $(VCSSVN_OBJS)
 
-export DEFAULT_EDITOR DEFAULT_PAGER
+export DEFAULT_EDITOR DEFAULT_PAGER DEFAULT_DOC_TARGET
 
 doc:
-	$(MAKE) -C Documentation all
+	$(MAKE) -C Documentation $(DEFAULT_DOC_TARGET)
 
 man:
 	$(MAKE) -C Documentation man