Add configure option to generate html man pages.

  ./configure --enable-htmldoc will now use asciidoctor to build
  and then install .html versions of the manual pages (with a
  table of contents) in $FVWM_DATADIR/htmldoc.

configure.ac

@@ -142,7 +142,7 @@ AC_ARG_ENABLE(package-subdirs,
 
 FVWM_MODULEDIR='${libexecdir}'"$FVWM_MODULESUBDIR"
 FVWM_DATADIR='${datadir}'"$FVWM_DATASUBDIR"
-FVWM_DOCDIR='${datadir}'"$FVWM_DOCSUBDIR"
+FVWM_DOCDIR='${datadir}'"$FVWM_DATASUBDIR/htmldoc"
 FVWM_PERLLIBDIR='${datadir}'"$FVWM_DATASUBDIR/perllib"
 FVWM_CONFDIR='${sysconfdir}'dnl used _only_ to search for system.fvwm2rc
 
@@ -321,6 +321,35 @@ if test ! x"$with_mandoc" = xno; then
 fi
 AM_CONDITIONAL([FVWM_BUILD_MANDOC], [test x"$with_mandoc" = xyes])
 
+AC_ARG_ENABLE(htmldoc,
+  AS_HELP_STRING([--enable-htmldoc],
+    [enable generation of html man pages]),
+  [ if test x"$enableval" = xyes; then
+		with_htmldoc="yes, check"
+	else
+		with_htmldoc="no"
+		problem_htmldoc=": Explicitly disabled"
+	fi ],
+	[ with_htmldoc="no" ]
+)
+
+if test ! x"$with_htmldoc" = xno; then
+	if test x"$ASCIIDOC" = x ; then
+		with_htmldoc="no"
+		problem_htmldoc=": No asciidoctor found in PATH"
+	elif test x"$SED" = x ; then
+		with_htmldoc="no"
+		problem_htmldoc=": No sed found in PATH"
+	elif test x"$HAVE_PERL_FOR_DOCS" = x0 ; then
+		with_htmldoc="no"
+		problem_htmldoc=": No perl found in PATH"
+	else
+		with_htmldoc="yes"
+	fi
+fi
+AM_CONDITIONAL([FVWM_BUILD_HTMLDOC], [test x"$with_htmldoc" = xyes])
+AM_CONDITIONAL([FVWM_BUILD_DOC], [test x"$with_mandoc" = xyes || test x"$with_htmldoc" = xyes])
+
 # ********* session management
 # Check the availability of SM; we don't have to add any extra libraries,
 # since -lSM -lICE are in X_PRE_LIBS when they exist.
@@ -1461,7 +1490,7 @@ Fvwm3 Configuration:
   Man pages:   $my_mandir
   Modules:     $my_moddir
   Data files:  $my_datdir
-  Doc files:   $my_docdir
+  HTML docs:   $my_docdir
   Perl lib:    $my_plldir
   Locale msg:  $my_localedir $INST_LINGUAS
 
@@ -1479,5 +1508,6 @@ Fvwm3 Configuration:
   With Xrender image support?         $with_xrender$problem_xrender
   With Golang support?                $with_golang$problem_golang
   Build man pages?                    $with_mandoc$problem_mandoc
+  Build html man pages?               $with_htmldoc$problem_htmldoc
 
-"
+"

doc/Makefile.am

@@ -22,22 +22,30 @@ EXTRA_DIST = $(MODULE_ADOC_SRCS)
 nothing:
 
 clean:
-	rm -f *.1 *.ad
+	rm -f *.1 *.ad *.html
 
 distclean-local: clean
 
-if FVWM_BUILD_MANDOC
+if FVWM_BUILD_DOC
 M1M = $(filter-out fvwm3_manpage_source.adoc, $(MODULE_ADOC))
+if FVWM_BUILD_MANDOC
 man1_MANS = $(patsubst %.adoc,%.1, $(M1M))
+endif
+if FVWM_BUILD_HTMLDOC
+html_MANS = $(patsubst %.adoc,%.html, $(M1M))
+doc_DATA = $(patsubst %.adoc,%.html, $(M1M))
+endif
+
 EXTRACT_SECTIONS = \
 	commands \
 	menus \
 	styles
 SECTION_FILES = $(patsubst %,fvwm3_%.ad, $(EXTRACT_SECTIONS))
 
 all: docs
-docs: $(man1_MANS)
+docs: $(man1_MANS) $(html_MANS)
 $(man1_MANS): $(SECTION_FILES)
+$(html_MANS): $(SECTION_FILES)
 
 %.ad: fvwm3_manpage_source.adoc
 	SECTION=$(patsubst fvwm3_%.ad,%,$@); \
@@ -48,4 +56,8 @@ $(man1_MANS): $(SECTION_FILES)
 
 %.1: %.adoc
 	"$(ASCIIDOC)" -b manpage -a "$(patsubst %.1,%,$@)" "$<" -o "$@"
+
+%.html: %.adoc
+	"$(ASCIIDOC)" -b html5 -a toc -a "$(patsubst %.html,%,$@)" "$<" -o "$@"
+
 endif