[babl] configure: try to add -Ofast to CFLAGS

[Øyvind Kolås <ok src gnome org>]

commit 90e25d7ff381fc67588d77bb033992079bab5d3a
Author: Øyvind Kolås <pippin gimp org>
Date:   Tue May 15 21:06:16 2018 +0200

    configure: try to add -Ofast to CFLAGS

 configure.ac |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 8aa37c5..9117248 100644
--- a/configure.ac
+++ b/configure.ac
@@ -161,6 +161,9 @@ CFLAGS="$CFLAGS $extra_warnings"
 BABL_DETECT_CFLAGS(extra_warnings, '-Wold-style-definition')
 CFLAGS="$CFLAGS $extra_warnings"
 
+BABL_DETECT_CFLAGS(extra_warnings, '-Ofast' )
+CFLAGS="$CFLAGS $extra_warnings"
+
 fi
 
 AC_PATH_PROG(RSVG, rsvg-convert, no)