diff --git a/configure.ac b/configure.ac
index 826f4f6c9282219138f18c618e40d199bc62de25..c0d017410222fc0d61855212a8882af0249d2618 100644
--- a/configure.ac
+++ b/configure.ac
@@ -432,7 +432,7 @@ AC_CHECK_FUNCS([getopt_long],[],
 	[AC_LIBOBJ([getopt])
 	AC_LIBOBJ([getopt1])
 	NEED_GETOPT=1
-	GNUCOMPAT_INCLUDE_PATH='$(top_srcdir)/gnu-compat/'])
+	GNUCOMPAT_INCLUDE_PATH='-I$(top_srcdir)/gnu-compat/'])
 AC_SUBST([GNUCOMPAT_INCLUDE_PATH])
 AM_CONDITIONAL(NEED_GETOPT, [test "x${NEED_GETOPT}" = "x1"])