[gnome-shell] configure.ac: Remove deprecated macro

[Jasper St. Pierre <jstpierre src gnome org>]

commit cdd354739a2f23ee73e005fdccaa7a774a8f698c
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Fri Jan 18 23:31:00 2013 -0500

    configure.ac: Remove deprecated macro
    
    AM_PROG_CC_C_O has been deprecated upstream for some time now.
    
    As a side effect, this makes "git grep taskpanel" turn up blank!
    
    https://bugzilla.gnome.org/show_bug.cgi?id=692052

 configure.ac |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 11dcafe..119b851 100644
--- a/configure.ac
+++ b/configure.ac
@@ -16,8 +16,6 @@ m4_ifdef([AM_SILENT_RULES],[AM_SILENT_RULES([yes])])
 
 # Checks for programs.
 AC_PROG_CC
-# Needed for per-target cflags, like in gnomeshell-taskpanel
-AM_PROG_CC_C_O
 
 # Initialize libtool
 LT_PREREQ([2.2.6])