[gnome-boxes] Add AM_PROG_AR to configure.ac

[Alexander Larsson <alexl src gnome org>]

commit aa7c3edc354ddc449dab5a331f2da0fb3f527892
Author: Alexander Larsson <alexl redhat com>
Date:   Fri Aug 17 05:22:43 2012 -0400

    Add AM_PROG_AR to configure.ac
    
    Without this I get an warning about linking libgdprivate-1.0.la
    "using a non-POSIX archiver", which can be removed by adding
    AM_PROG_AR.

 configure.ac |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 88cd38e..c097a94 100644
--- a/configure.ac
+++ b/configure.ac
@@ -19,6 +19,7 @@ AM_SILENT_RULES([yes])
 AC_PROG_CC
 AM_PROG_CC_C_O
 AC_PROG_CXX
+AM_PROG_AR
 
 # Initialize libtool
 LT_PREREQ([2.2])