Documentation: tighten dependency for git.{html,txt}

Every time _any_ documentation page changed, cmds-*.txt files
were regenerated, which caused git.{html,txt} to be remade.  Try
not to update cmds-*.txt files if their new contents match the
old ones.

Signed-off-by: Junio C Hamano <[email protected]>

Documentation/Makefile

@@ -85,14 +85,17 @@ cmds_txt = cmds-ancillaryinterrogators.txt \
 	cmds-purehelpers.txt \
 	cmds-foreignscminterface.txt
 
-$(cmds_txt): cmd-list.perl $(MAN1_TXT)
+$(cmds_txt): cmd-list.made
+
+cmd-list.made: cmd-list.perl $(MAN1_TXT)
 	perl ./cmd-list.perl
+	date >$@
 
 git.7 git.html: git.txt core-intro.txt
 
 clean:
 	rm -f *.xml *.html *.1 *.7 howto-index.txt howto/*.html doc.dep
-	rm -f $(cmds_txt)
+	rm -f $(cmds_txt) *.made
 
 %.html : %.txt
 	$(ASCIIDOC) -b xhtml11 -d manpage -f asciidoc.conf $(ASCIIDOC_EXTRA) $<

Documentation/cmd-list.perl

@@ -1,8 +1,11 @@
-#
+#!/usr/bin/perl -w
+
+use File::Compare qw(compare);
 
 sub format_one {
 	my ($out, $name) = @_;
 	my ($state, $description);
+	$state = 0;
 	open I, '<', "$name.txt" or die "No such file $name.txt";
 	while (<I>) {
 		if (/^NAME$/) {
@@ -55,7 +58,14 @@ sub format_one {
 		format_one(\*O, $_);
 	}
 	close O;
-	rename "$out+", "$out";
+
+	if (-f "$out" && compare("$out", "$out+") == 0) {
+		unlink "$out+";
+	}
+	else {
+		print STDERR "$out\n";
+		rename "$out+", "$out";
+	}
 }
 
 __DATA__