diff --git a/configure.ac b/configure.ac
index 94e2a8a..fd7fbad 100644
--- a/configure.ac
+++ b/configure.ac
@@ -578,6 +578,7 @@ AC_PROG_CC
 AC_PROG_CPP
 if test -n "$FORTRAN"; then
     AC_PROG_FC
+    AC_PROG_F77
     AC_FC_LIBRARY_LDFLAGS
     AC_FC_WRAPPERS
 fi