diff --git a/Tests/FindPackageModeMakefileTest/foo.cpp b/Tests/FindPackageModeMakefileTest/foo.cpp
index 6aea22629a..7cb9381edc 100644
--- a/Tests/FindPackageModeMakefileTest/foo.cpp
+++ b/Tests/FindPackageModeMakefileTest/foo.cpp
@@ -1,3 +1,5 @@
+#include "foo.h"
+
 int foo()
 {
   return 1477;
diff --git a/Tests/FindPackageModeMakefileTest/foo.h b/Tests/FindPackageModeMakefileTest/foo.h
index 4ec598ad51..7051edac43 100644
--- a/Tests/FindPackageModeMakefileTest/foo.h
+++ b/Tests/FindPackageModeMakefileTest/foo.h
@@ -1,6 +1,14 @@
 #ifndef FOO_H
 #define FOO_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 int foo();
 
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
 #endif