add AC_PROC_SED
diff --git a/configure.ac b/configure.ac
index 9982110..e6f4982 100755
--- a/configure.ac
+++ b/configure.ac
@@ -61,7 +61,9 @@
 dnl --------------------
 AC_PROG_CC
 AC_PROG_CPP
+
 AC_PROG_EGREP
+AC_PROG_SED
 
 dnl ------------------------------------------------------------------
 dnl Intel compiler check. Although Intel tries really hard to make icc