diff --git a/config/ompi_ext.m4 b/config/ompi_ext.m4
index 9f0560820e..40be85af98 100644
--- a/config/ompi_ext.m4
+++ b/config/ompi_ext.m4
@@ -456,7 +456,7 @@ AC_DEFUN([EXT_PROCESS_COMPONENT],[
 
     AC_MSG_CHECKING([if MPI Extension $component has C bindings])
 
-    AS_IF([test ! -e "$test_header"],
+    AS_IF([test ! -e "$test_header" && test ! -e "$test_header.in"],
           [ # There *must* be C bindings
            AC_MSG_RESULT([no])
            AC_MSG_WARN([C bindings for MPI extensions are required])