Add script _build_fvwm3_man.sh to build fvwm3 manpages.

This script takes a single input, the location of the fvwm3 source,
and then builds all the manual pages and puts them in Man/. Run script
from top level of this source.

    ./_build_fvwm3_man.sh /path/to/fvwm3_source

This script is meant to be used with the fvwm3 release CI scripts
to update the manual pages at that time.

_build_fvwm3_man.sh

@@ -0,0 +1,70 @@
+#!/bin/sh
+#
+# This script uses asciidoctor to build the html documents for the fvwm3
+# manual pages from the fvwm3 source. The script takes a single input,
+# the full path to the fvwm3 source.
+# 
+#     _build_fvwm3_man.sh /path/to/fvwm3_source
+
+# Check for asciidoctor and input is root of fvwm3 source.
+if [ ! -f "_build_fvwm3_man.sh" ]
+then
+	echo "Script must be run in root directory of source."
+	exit 1
+fi
+if [ -z "$1" ]
+then
+	echo "No input provided."
+	echo "Usage: _build_fvwm3_man.sh /path/to/fvwm3_source"
+	exit 1
+fi
+if [ ! -f "$1/doc/fvwm3_manpage_source.adoc" ]
+then
+	echo "Fvwm3 source not found at: $1"
+	exit 1
+fi
+if ! command -v asciidoctor >/dev/null 2>&1
+then
+	echo "Asciidoctor not found."
+	exit 1
+fi
+
+FVWM_DOC_SRC="$1/doc"
+FVWM_VER=`grep AC_INIT $1/configure.ac | awk '{print substr($2, 1, 5);}'`
+CMD="asciidoctor -e -b html5 -a toc -a webfonts!"
+FVWM_DOCS="fvwm3 fvwm3all fvwm3commands fvwm3menus fvwm3styles FvwmAnimate \
+	FvwmAuto FvwmBacker FvwmButtons FvwmCommand FvwmConsole FvwmEvent \
+	FvwmForm FvwmIconMan FvwmIdent FvwmMFL FvwmPager FvwmPerl FvwmPrompt \
+	FvwmRearrange FvwmScript fvwm-menu-desktop fvwm-menu-directory \
+	fvwm-menu-xlock fvwm-perllib fvwm-root fvwm-convert-2.6"
+
+# Build fvwm manual pages and modify the output from asciidoctor.
+for doc in ${FVWM_DOCS}
+do
+	IN_FILE=${FVWM_DOC_SRC}/${doc}.adoc
+	OUT_FILE=Man/${doc}.html
+	HEADER="---\ntitle: ${doc} manual page\nshowtitle: 1\n"
+	HEADER="${HEADER}permalink: /Man/${doc}/index.html\n---"
+	echo "Building: ${OUT_FILE}"
+	echo ${HEADER} > ${OUT_FILE}
+	${CMD} -a ${doc} ${IN_FILE} -o - >> ${OUT_FILE}
+	sed -i 's/literalblock/literalblock highlight/' ${OUT_FILE}
+	sed -i '/toctitle/d' ${OUT_FILE}
+	sed -i 's/id="toc" class="toc"/id="markdown-toc"/' ${OUT_FILE}
+done
+
+# Build index page.
+IN_FILE=${FVWM_DOC_SRC}/index.adoc.in
+OUT_FILE=Man/index.html
+HEADER="---\ntitle: Fvwm3 Manual Pages\nshowtitle: 1\n---\n"
+HEADER="${HEADER}The following are the manual pages for "
+HEADER="${HEADER}fvwm3 version <strong>${FVWM_VER}</strong>."
+echo "Building: ${OUT_FILE}"
+echo ${HEADER} > ${OUT_FILE}
+${CMD} -a index ${IN_FILE} -o - >> ${OUT_FILE}
+sed -i 's!.html"!/"!' ${OUT_FILE}
+sed -i '/toctitle/d' ${OUT_FILE}
+sed -i 's/id="toc" class="toc"/id="markdown-toc"/' ${OUT_FILE}
+sed -i 's/ class="sect1"//' ${OUT_FILE}
+sed -i 's!<p>!!g' ${OUT_FILE}
+sed -i 's!</p>!!g' ${OUT_FILE}