Add support for a pdf version of the user manual

Use dblatex in order to create a pdf version of the git user manual.  No
existing Makefile targets (including "all") are touched, so you need to
explicitly say

make pdf
sudo make install-pdf

to get user-manual.pdf created and installed.

Signed-off-by: Miklos Vajna <vmiklos@frugalware.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/Makefile

@@ -32,6 +32,7 @@ DOC_MAN7=$(patsubst %.txt,%.7,$(MAN7_TXT))
 prefix?=$(HOME)
 bindir?=$(prefix)/bin
 htmldir?=$(prefix)/share/doc/git-doc
+pdfdir?=$(prefix)/share/doc/git-doc
 mandir?=$(prefix)/share/man
 man1dir=$(mandir)/man1
 man5dir=$(mandir)/man5
@@ -50,6 +51,7 @@ infodir?=$(prefix)/share/info
 MAKEINFO=makeinfo
 INSTALL_INFO=install-info
 DOCBOOK2X_TEXI=docbook2x-texi
+DBLATEX=dblatex
 ifndef PERL_PATH
 	PERL_PATH = /usr/bin/perl
 endif
@@ -87,6 +89,8 @@ man7: $(DOC_MAN7)
 
 info: git.info gitman.info
 
+pdf: user-manual.pdf
+
 install: install-man
 
 install-man: man
@@ -107,6 +111,10 @@ install-info: info
 	  echo "No directory found in $(DESTDIR)$(infodir)" >&2 ; \
 	fi
 
+install-pdf: pdf
+	$(INSTALL) -d -m 755 $(DESTDIR)$(pdfdir)
+	$(INSTALL) -m 644 user-manual.pdf $(DESTDIR)$(pdfdir)
+
 install-html: html
 	sh ./install-webdoc.sh $(DESTDIR)$(htmldir)
 
@@ -190,6 +198,11 @@ user-manual.texi: user-manual.xml
 	$(DOCBOOK2X_TEXI) user-manual.xml --to-stdout | $(PERL_PATH) fix-texi.perl >$@+
 	mv $@+ $@
 
+user-manual.pdf: user-manual.xml
+	$(RM) $@+ $@
+	$(DBLATEX) -o $@+ -p /etc/asciidoc/dblatex/asciidoc-dblatex.xsl -s /etc/asciidoc/dblatex/asciidoc-dblatex.sty $<
+	mv $@+ $@
+
 gitman.texi: $(MAN_XML) cat-texi.perl
 	$(RM) $@+ $@
 	($(foreach xml,$(MAN_XML),$(DOCBOOK2X_TEXI) --to-stdout $(xml);)) | \

INSTALL

@@ -101,6 +101,9 @@ Issues of note:
    Building and installing the info file additionally requires
    makeinfo and docbook2X.  Version 0.8.3 is known to work.
 
+   Building and installing the pdf file additionally requires
+   dblatex.  Version 0.2.7 with asciidoc >= 8.2.7 is known to work.
+
    The documentation is written for AsciiDoc 7, but "make
    ASCIIDOC8=YesPlease doc" will let you format with AsciiDoc 8.
 

Makefile

@@ -1306,6 +1306,9 @@ html:
 info:
 	$(MAKE) -C Documentation info
 
+pdf:
+	$(MAKE) -C Documentation pdf
+
 TAGS:
 	$(RM) TAGS
 	$(FIND) . -name '*.[hcS]' -print | xargs etags -a
@@ -1448,6 +1451,9 @@ install-html:
 install-info:
 	$(MAKE) -C Documentation install-info
 
+install-pdf:
+	$(MAKE) -C Documentation install-pdf
+
 quick-install-doc:
 	$(MAKE) -C Documentation quick-install