[PATCH 5/7] doc: Allow rst2man.py as an alternative to rst2man

[W. Trevor King]

Gentoo's dev-python/docutils-0.10 installs Docutils scripts with a
*.py extension, so I have /usr/bin/rst2man.py and no rst2man script.
This patch supports users with both types of systems by checking for
rst2man, falling back on rst2man.py, and giving up only if neither is
found.  Users can also set the new RST2MAN path variable explicitly
when they call Make:

  make RST2MAN=/my/custom/rst_to_man_converter build-man

I use POSIX's 'command -v' [1] to find the path to rst2man or
rst2man.py, and save that as RST2MAN in Makefile.config.  We can use a
non-empty RST2MAN to check for the availability of an rst2man program,
so there's no need for a separate HAVE_RST2MAN.  Then pass the
configured RST2MAN path through to prerst2man.py to use in its system
call.

[1]: http://pubs.opengroup.org/onlinepubs/9699919799/utilities/command.html
---
 configure          | 12 +++++++-----
 doc/Makefile.local |  6 +++---
 doc/prerst2man.py  |  9 +++++----
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/configure b/configure
index 1d430b9..81c286b 100755
--- a/configure
+++ b/configure
@@ -400,7 +400,6 @@ printf "Checking if sphinx is available and supports nroff output... "
 if hash sphinx-build > /dev/null 2>&1 && python -m sphinx.writers.manpage > /dev/null 2>&1 ; then
     printf "Yes.\n"
     have_sphinx=1
-    have_rst2man=0
 else
     printf "No (falling back to rst2man).\n"
     have_sphinx=0
@@ -408,10 +407,12 @@ else
     printf "Checking if rst2man is available... "
     if rst2man -V > /dev/null 2>&1; then
        printf "Yes.\n"
-       have_rst2man=1
+       RST2MAN=$(command -v rst2man)
+    elif rst2man.py -V > /dev/null 2>&1; then
+       printf "Yes.\n"
+       RST2MAN=$(command -v rst2man.py)
     else
        printf "No (so will not install man pages).\n"
-       have_rst2man=0
     fi
 fi
 
@@ -788,8 +789,9 @@ HAVE_EMACS = ${have_emacs}
 # Whether there's a sphinx-build binary available for building documentation
 HAVE_SPHINX=${have_sphinx}
 
-# Whether there's a rst2man binary available for building documentation
-HAVE_RST2MAN=${have_rst2man}
+# The path to the rst2man program for building documentation.  Set to
+# an empty string if no such program is available.
+RST2MAN=${RST2MAN}
 
 # The directory to which desktop files should be installed
 desktop_dir = \$(prefix)/share/applications
diff --git a/doc/Makefile.local b/doc/Makefile.local
index 0980c71..e08fc99 100644
--- a/doc/Makefile.local
+++ b/doc/Makefile.local
@@ -42,8 +42,8 @@ ifeq ($(HAVE_SPHINX),1)
 	    mkdir -p $(DOCBUILDDIR)/man/man$${section}; \
 	    mv $(DOCBUILDDIR)/man/*.$${section} $(DOCBUILDDIR)/man/man$${section}; \
 	done
-else ifeq ($(HAVE_RST2MAN),1)
-	$(prerst2man) $(srcdir)/doc $(DOCBUILDDIR)/man
+else ifdef RST2MAN
+	$(prerst2man) "$(RST2MAN)" $(srcdir)/doc $(DOCBUILDDIR)/man
 else
 	@echo "Fatal: build dependency fail."
 	@false
@@ -51,7 +51,7 @@ endif
 
 # Do not try to build or install man pages if a man page converter is
 # not available.
-ifeq ($(HAVE_SPHINX)$(HAVE_RST2MAN),00)
+ifeq ($(HAVE_SPHINX)$(RST2MAN),0)
 build-man:
 install-man:
 	@echo "No sphinx or rst2man, will not install man pages."
diff --git a/doc/prerst2man.py b/doc/prerst2man.py
index 437dea9..81ce817 100644
--- a/doc/prerst2man.py
+++ b/doc/prerst2man.py
@@ -4,8 +4,9 @@ from os.path import dirname, isdir
 from os import makedirs, system
 import re
 
-sourcedir = argv[1]
-outdir = argv[2]
+rst2man = argv[1]
+sourcedir = argv[2]
+outdir = argv[3]
 
 if not isdir(outdir):
     makedirs(outdir, 0o755)
@@ -59,5 +60,5 @@ for page in man_pages:
     outfile.write("".join(lines))
     outfile.close()
 
-    system('set -x; rst2man {0} {1}/{2}.{3}'
-           .format(filename, outdir, page[0], page[4]))
+    system('set -x; {0} {1} {2}/{3}.{4}'
+           .format(rst2man, filename, outdir, page[0], page[4]))
-- 
1.9.1.353.gc66d89d