[pan2] Use automake's 'quieter builds' rule when available

[Charles Stephen Kerr <csk src gnome org>]

commit 910fe78e9cc255d1708a076ac72b4ae8481d3b49
Author: Charles Kerr <charles rebelbase com>
Date:   Sun Sep 27 23:09:26 2009 -0500

    Use automake's 'quieter builds' rule when available

 configure.in |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/configure.in b/configure.in
index a9cac52..b0a8c51 100644
--- a/configure.in
+++ b/configure.in
@@ -11,6 +11,8 @@ AC_CONFIG_SRCDIR(pan/general/quark.cc)
 AM_INIT_AUTOMAKE(AC_PACKAGE_NAME,AC_PACKAGE_VERSION)
 AM_MAINTAINER_MODE
 
+m4_ifdef([AM_SILENT_RULES],[AM_SILENT_RULES([yes])])
+
 dnl pcre, glib, gmime, and gtk are manditory prerequisites.
 dnl
 dnl GtkSpell is optional: GTKSPELL_REQUIRED refers to the minimum version