[PATCH 1/3] maint: check for dot before using it

[Akim Demaille]

* configure.ac: here.
* doc/Makefile.am: Use $(DOT).
Ship the generated files, to spare the user the need for Graphviz.
---
 README-hacking  | 25 +++++++++++++------------
 configure.ac    |  1 +
 doc/Makefile.am | 17 ++++++++++-------
 3 files changed, 24 insertions(+), 19 deletions(-)

diff --git a/README-hacking b/README-hacking
index 26391e9..11b9f82 100644
--- a/README-hacking
+++ b/README-hacking
@@ -43,16 +43,17 @@ These requirements do not apply when building from a 
distribution tarball.
 
 ** Requirements
 
-We've opted to keep only the highest-level sources in the repository.
-This eases our maintenance burden, (fewer merges etc.), but imposes more
+We've opted to keep only the highest-level sources in the repository.  This
+eases our maintenance burden, (fewer merges etc.), but imposes more
 requirements on anyone wishing to build from the just-checked-out sources.
 For example, you have to use the latest stable versions of the maintainer
 tools we depend upon, including:
 
-- Automake <http://www.gnu.org/software/automake/>
 - Autoconf <http://www.gnu.org/software/autoconf/>
+- Automake <http://www.gnu.org/software/automake/>
 - Flex <http://www.gnu.org/software/flex/>
 - Gettext <http://www.gnu.org/software/gettext/>
+- Graphviz <http://www.graphviz.org>
 - Gzip <http://www.gnu.org/software/gzip/>
 - Perl <http://www.cpan.org/>
 - Rsync <http://samba.anu.edu.au/rsync/>
@@ -61,16 +62,16 @@ tools we depend upon, including:
 Valgrind <http://valgrind.org/> is also highly recommended, if it supports
 your architecture.
 
-Bison is written using Bison grammars, so there are bootstrapping
-issues.  The bootstrap script attempts to discover when the C code
-generated from the grammars is out of date, and to bootstrap with an
-out-of-date version of the C code, but the process is not foolproof.
-Also, you may run into similar problems yourself if you modify Bison.
+Bison is written using Bison grammars, so there are bootstrapping issues.
+The bootstrap script attempts to discover when the C code generated from the
+grammars is out of date, and to bootstrap with an out-of-date version of the
+C code, but the process is not foolproof.  Also, you may run into similar
+problems yourself if you modify Bison.
 
-Only building the initial full source tree will be a bit painful.
-Later, after synchronizing from the repository a plain 'make' should
-be sufficient.  Note, however, that when gnulib is updated, running
-'./bootstrap' again might be needed.
+Only building the initial full source tree will be a bit painful.  Later,
+after synchronizing from the repository a plain 'make' should be sufficient.
+Note, however, that when gnulib is updated, running './bootstrap' again
+might be needed.
 
 ** First checkout
 
diff --git a/configure.ac b/configure.ac
index 4cc9ef9..6a0e9c4 100644
--- a/configure.ac
+++ b/configure.ac
@@ -115,6 +115,7 @@ AC_SUBST([YACC_SCRIPT])
 AC_SUBST([YACC_LIBRARY])
 
 # Checks for programs.
+AM_MISSING_PROG([DOT], [dot])
 AC_PROG_LEX
 $LEX_IS_FLEX || AC_MSG_ERROR([Flex is required])
 AC_PROG_YACC
diff --git a/doc/Makefile.am b/doc/Makefile.am
index 9c650bf..9c9c24c 100644
--- a/doc/Makefile.am
+++ b/doc/Makefile.am
@@ -101,26 +101,29 @@ nodist_man_MANS = yacc.1
 ## ----------------------------- ##
 
 CLEANDIRS += figs
-EXTRA_DIST += figs/example-reduce.dot figs/example-shift.dot
+FIGS_DOT = figs/example-reduce.dot figs/example-shift.dot
+EXTRA_DIST +=                                                          \
+  $(FIGS_DOT)                                                          \
+  $(FIGS_DOT:.dot=.eps) $(FIGS_DOT:.dot=.pdf) $(FIGS_DOT:.dot=.png)
 SUFFIXES += .dot .eps .pdf .png
 
-bison.dvi: figs/example-reduce.eps figs/example-shift.eps
-bison.html: figs/example-reduce.png figs/example-shift.png
-bison.pdf: figs/example-reduce.pdf figs/example-shift.pdf
+bison.dvi:  $(FIGS_DOT:.dot=.eps)
+bison.html: $(FIGS_DOT:.dot=.png)
+bison.pdf:  $(FIGS_DOT:.dot=.pdf)
 
 .dot.eps:
        $(AM_V_GEN) $(MKDIR_P) `echo "./$@" | sed -e 's,/[^/]*$$,,'`
-       $(AM_V_at) dot -Teps $< >address@hidden
+       $(AM_V_at) $(DOT) -Gmargin=0 -Teps $< >address@hidden
        $(AM_V_at) mv address@hidden $@
 
 .dot.pdf:
        $(AM_V_GEN) $(MKDIR_P) `echo "./$@" | sed -e 's,/[^/]*$$,,'`
-       $(AM_V_at) dot -Tpdf -Gmargin=0 $< >address@hidden
+       $(AM_V_at) $(DOT) -Gmargin=0 -Tpdf $< >address@hidden
        $(AM_V_at) mv address@hidden $@
 
 .dot.png:
        $(AM_V_GEN) $(MKDIR_P) `echo "./$@" | sed -e 's,/[^/]*$$,,'`
-       $(AM_V_at) dot -Tpng $< >address@hidden
+       $(AM_V_at) $(DOT) -Gmargin=0 -Tpng $< >address@hidden
        $(AM_V_at) mv address@hidden $@
 
 ## -------------- ##
-- 
1.7.12.2