diff --git a/src/mca/oob/base/base.h b/src/mca/oob/base/base.h
index 4b5022c2e2..56ffab6a69 100644
--- a/src/mca/oob/base/base.h
+++ b/src/mca/oob/base/base.h
@@ -19,7 +19,7 @@
  * This is the first module on the list. This is here temporarily
  * to make things work
  */
-mca_oob_t mca_oob;
+extern mca_oob_t mca_oob;
 
 /**
  * the module data structure
diff --git a/src/mca/oob/base/oob_base_open.c b/src/mca/oob/base/oob_base_open.c
index 6d09c66e1e..d75ab63d7c 100644
--- a/src/mca/oob/base/oob_base_open.c
+++ b/src/mca/oob/base/oob_base_open.c
@@ -21,6 +21,7 @@
 /*
  * Global variables
  */
+mca_oob_t mca_oob;
 int mca_oob_base_output = -1;
 ompi_list_t mca_oob_base_components;
 ompi_list_t mca_oob_base_modules;