[cogl] configure.ac: Add the check for the ffs function

[Neil Roberts <nroberts src gnome org>]

commit 3919f3e97eca078e6bdbbeb1e45886de161d839e
Author: Neil Roberts <neil linux intel com>
Date:   Fri May 6 17:21:30 2011 +0100

    configure.ac: Add the check for the ffs function
    
    When Cogl was sharing Clutter's configure script, it had a check for
    the ffs function of libc so that it can provide a fallback if it is
    not available. This fallback was missed in the split out so Cogl would
    end up always using the fallback.

 configure.ac |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 5c424e4..d6bb438 100644
--- a/configure.ac
+++ b/configure.ac
@@ -688,6 +688,9 @@ dnl ================================================================
 dnl Checks for library functions.
 dnl ================================================================
 
+dnl The 'ffs' function is part of C99 so it isn't always
+dnl available. Cogl has a fallback if needed.
+AC_CHECK_FUNCS([ffs])
 
 dnl ================================================================
 dnl What needs to be substituted in other files