reduce unnecessary documentation rebuilds

Makefile.in

@@ -1343,10 +1343,12 @@ start-gforth.el:	gforth.el
 #Documentation
 
 doc/doc.fd:	doc/makedoc.fs $(GFORTH_FI_SRC) $(EXTRA_DOC)
-		$(FORTHK) -e "s\" doc/doc.fd\"" doc/makedoc.fs except.fs startup.fs $(EXTRA_DOC) -e bye
+		$(FORTHK) -e "s\" doc/doc.fd.tmp\"" doc/makedoc.fs except.fs startup.fs $(EXTRA_DOC) -e bye
+		$(srcdir)/move-if-change doc/doc.fd.tmp $@
 
 doc/crossdoc.fd:	$(KERN_SRC) kernel/version.fs $(FORTH_GEN0)
 		$(FORTHK) -e 's" mach32l.fs" include kernel/main.fs' -e bye
+		$(srcdir)/move-if-change doc/crossdoc.fd.tmp $@
 
 doc/gforth.texi: doc/gforth.texi.in prim.b ds2texi.fs prims2x.fs \
 		doc/doc.fd doc/crossdoc.fd preforth @kernel_fi@
@@ -1360,7 +1362,7 @@ checkdoc:	doc/gforth.texi.in prim.b ds2texi.fs prims2x.fs doc/doc.fd doc/crossdo
 
 doc/gforth.txt:	txt
 
-doc pdf dvi txt ps html:	gforth.fi $(GFORTH_TEXI) $(VMGEN_TEXI) TAGS doc/Makefile
+doc pdf dvi txt ps html: $(GFORTH_TEXI) $(VMGEN_TEXI) doc/Makefile
 		-cd doc; $(MAKE) $@
 
 # For an explanation of the following Makefile rules, see node

cross.fs

@@ -2250,7 +2250,7 @@ X has? f83headerstring [IF]
 
 \ Target Document Creation (goes to crossdoc.fd)       05jul95py
 
-s" ./doc/crossdoc.fd" r/w create-file throw value doc-file-id
+s" ./doc/crossdoc.fd.tmp" r/w create-file throw value doc-file-id
 \ contains the file-id of the documentation file
 
 : T-\G ( -- )

move-if-change

+#!/bin/sh
+# Like mv $1 $2, but if the files are the same, just delete $1.
+# Status is zero if successful, nonzero otherwise.
+
+VERSION='2016-01-11 22:04'; # UTC
+# The definition above must lie within the first 8 lines in order
+# for the Emacs time-stamp write hook (at end) to update it.
+# If you change this file with Emacs, please let the write hook
+# do its job.  Otherwise, update this string manually.
+
+# Copyright (C) 2002-2016 Free Software Foundation, Inc.
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+usage="usage: $0 SOURCE DEST"
+
+help="$usage
+  or:  $0 OPTION
+If SOURCE is different than DEST, then move it to DEST; else remove SOURCE.
+
+  --help     display this help and exit
+  --version  output version information and exit
+
+The variable CMPPROG can be used to specify an alternative to 'cmp'.
+
+Report bugs to <bug-gnulib@gnu.org>."
+
+version=`expr "$VERSION" : '\([^ ]*\)'`
+version="move-if-change (gnulib) $version
+Copyright (C) 2011 Free Software Foundation, Inc.
+License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law."
+
+cmpprog=${CMPPROG-cmp}
+
+for arg
+do
+  case $arg in
+    --help | --hel | --he | --h)
+      exec echo "$help" ;;
+    --version | --versio | --versi | --vers | --ver | --ve | --v)
+      exec echo "$version" ;;
+    --)
+      shift
+      break ;;
+    -*)
+      echo "$0: invalid option: $arg" >&2
+      exit 1 ;;
+    *)
+      break ;;
+  esac
+done
+
+test $# -eq 2 || { echo "$0: $usage" >&2; exit 1; }
+
+if test -r "$2" && $cmpprog -- "$1" "$2" >/dev/null; then
+  rm -f -- "$1"
+else
+  if mv -f -- "$1" "$2"; then :; else
+    # Ignore failure due to a concurrent move-if-change.
+    test -r "$2" && $cmpprog -- "$1" "$2" >/dev/null && rm -f -- "$1"
+  fi
+fi
+
+## Local Variables:
+## eval: (add-hook 'write-file-hooks 'time-stamp)
+## time-stamp-start: "VERSION='"
+## time-stamp-format: "%:y-%02m-%02d %02H:%02M"
+## time-stamp-time-zone: "UTC0"
+## time-stamp-end: "'; # UTC"
+## End: