[libxml2] configure: support silent automake rules if possible

[Stefan Kost <stefkost src gnome org>]

commit c9c939d614bc6dd6579b11a872e3d2f55b3e4885
Author: Stefan Kost <ensonic users sf net>
Date:   Tue May 10 10:34:41 2011 +0300

    configure: support silent automake rules if possible
    
    This gives us a much less noisy build and makes error stand out a lot more.

 configure.in |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)
---
diff --git a/configure.in b/configure.in
index a1d2c89..45c939e 100644
--- a/configure.in
+++ b/configure.in
@@ -50,6 +50,11 @@ VERSION=${LIBXML_VERSION}
 
 AM_INIT_AUTOMAKE(libxml2, $VERSION)
 
+# Support silent build rules, requires at least automake-1.11. Disable
+# by either passing --disable-silent-rules to configure or passing V=1
+# to make
+m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
+
 dnl Checks for programs.
 AC_PROG_CC
 AC_PROG_INSTALL