docs: clean up a bit and support `NaturalDocs`

Some installs use `NaturalDocs` instead of `naturaldocs`,
so add support for either form.

bootstrap.sh

@@ -2,24 +2,19 @@
 # $Id$
 # Small shell script to build gd from source
 
+v() { echo "$@"; "$@"; }
+
 # Generate the manual (unless naturaldocs isn't installed).  Source
 # dists should include the docs so that end users don't need to
 # install naturaldocs.  At the same time, we tolerate it being missing
 # so that random hackers don't need it just to build the code.
-if which naturaldocs >/dev/null 2>&1 ; then
-	echo "Generation user docs:"
-	(cd docs/naturaldocs; bash run_docs.sh)
-else
-	echo "Can't find naturaldocs; not generating user manual."
-fi
-
+v docs/naturaldocs/run_docs.sh --nonfatal
 
 if echo "${OSTYPE:-$(uname)}" | grep -q '^darwin' ; then
 	echo "Having trouble on OS X? Try: brew install autoconf libtool automake gettext apple-gcc42 pkg-config cmake"
 fi
 
-echo "autoreconf -f -i"
-if ! autoreconf -f -i ; then
+if ! v autoreconf -f -i ; then
 	exit 1
 fi
 

docs/naturaldocs/run_docs.sh

@@ -1,18 +1,61 @@
-#!/bin/bash
+#!/bin/sh
 
 set -e
 
+usage() {
+	echo "Usage: run_docs.sh [--nonfatal]"
+	echo "Generate the manual for gd!"
+	if [ $# -ne 0 ] ; then
+		printf 'ERROR: %b\n' "$*"
+		exit 1
+	else
+		exit 0
+	fi
+}
+
+nd() {
+	# Figure out the name of this tool.
+	if which naturaldocs 2>/dev/null ; then
+		return
+	elif which NaturalDocs 2>/dev/null ; then
+		return
+	else
+		return 1
+	fi
+}
+
+cd "$(dirname "$0")"
+
+if [ $# -eq 1 ] ; then
+	case $1 in
+	--nonfatal)
+		if ! nd >/dev/null ; then
+			echo "skipping doc generation -- please install naturaldoc!"
+			exit 0
+		fi
+		;;
+	-h|--help)
+		usage
+		;;
+	*)
+		usage "unknown option: $1"
+		;;
+	esac
+elif [ $# -ne 0 ] ; then
+	usage "unknown options: $*"
+fi
+
 # Version number
 VERSION=`(cd ../../; perl config/getver.pl)`
 
 # Clear away old docs and ensure the doc dir. is present.
-[ -d html ] && rm -rf html
+rm -rf html
 mkdir html
 
 # Create a lightly-processed copy of the source to use as input.  This
 # file skips all non-C code in src/ and removes the BGD_DECLARE()
 # macro from definitions so they don't show up in the docs.
-[ -d tmp ] && rm -rf tmp
+rm -rf tmp
 mkdir tmp
 perl nobgd.pl ../../src/ tmp/
 
@@ -22,7 +65,7 @@ sed -e "s/@VERSION@/$VERSION/g" preamble.txt > tmp/preamble.txt
 # ^^^ hack to get the version number in the docs.
 
 # Run naturaldocs to create the manual.
-naturaldocs --rebuild --rebuild-output --documented-only \
+$(nd) --rebuild --rebuild-output --documented-only \
     -i tmp/ \
     -o html html  \
     --project project/