[PATCH] Rebuild manpage only if needed

[Maxim Dounin]

# HG changeset patch
# User Maxim Dounin <mdounin at mdounin.ru>
# Date 1309954638 -14400
# Node ID 81b04c4184dcff7dfdbd6ca12ad93f47e8718115
# Parent  1c167244d2fdb064c159012c50a7ae3fd1ed254a
Rebuild manpage only if needed.

diff --git a/auto/install b/auto/install
--- a/auto/install
+++ b/auto/install
@@ -74,7 +74,9 @@ esac
 
 cat << END                                                    >> $NGX_MAKEFILE
 
-manpage:
+manpage:	$NGX_OBJS/nginx.8
+
+$NGX_OBJS/nginx.8:	man/nginx.8 $NGX_AUTO_CONFIG_H
 	sed -e "s|%%PREFIX%%|$NGX_PREFIX|" \\
 		-e "s|%%PID_PATH%%|$NGX_PID_PATH|" \\
 		-e "s|%%CONF_PATH%%|$NGX_CONF_PATH|" \\