[build] fix default CFLAGS and squish warning

* configure.ac: Move down the AC_SYS_LARGEFILE test - it was setting CFLAGS
  and so disabling the default CFLAGS setting section.
  Squish warning by adding AC_CONFIG_MACRO_DIR on the reccommendation of
  autoreconf.
diff --git a/configure.ac b/configure.ac
index d7d8a2f..487aa43 100755
--- a/configure.ac
+++ b/configure.ac
@@ -10,6 +10,7 @@
 
 AC_INIT(Quagga, 0.99.13, [http://bugzilla.quagga.net])
 AC_CONFIG_SRCDIR(lib/zebra.h)
+AC_CONFIG_MACRO_DIR([m4])
 
 dnl -----------------------------------
 dnl Get hostname and other information.
@@ -28,8 +29,6 @@
 fi
 AC_ARG_VAR([GAWK],[GNU AWK])
 
-AC_SYS_LARGEFILE
-
 dnl default is to match previous behavior
 exampledir=${sysconfdir}
 AC_ARG_ENABLE([exampledir],
@@ -554,6 +553,8 @@
   ;;
 esac
 
+AC_SYS_LARGEFILE
+
 dnl ---------------------
 dnl Integrated VTY option
 dnl ---------------------