diff --git a/Tests/ObjectLibrary/A/CMakeLists.txt b/Tests/ObjectLibrary/A/CMakeLists.txt
index 04ab02f16..36c86e7e9 100644
--- a/Tests/ObjectLibrary/A/CMakeLists.txt
+++ b/Tests/ObjectLibrary/A/CMakeLists.txt
@@ -1,4 +1,4 @@
-project(ObjectLibraryA)
+project(ObjectLibraryA C)
 # Add -fPIC so objects can be used in shared libraries.
 # TODO: Need property for this.
 if(CMAKE_SHARED_LIBRARY_C_FLAGS AND NOT WATCOM)
diff --git a/Tests/ObjectLibrary/B/CMakeLists.txt b/Tests/ObjectLibrary/B/CMakeLists.txt
index 4b0b07d1c..32d8cebf6 100644
--- a/Tests/ObjectLibrary/B/CMakeLists.txt
+++ b/Tests/ObjectLibrary/B/CMakeLists.txt
@@ -1,4 +1,4 @@
-project(ObjectLibraryB)
+project(ObjectLibraryB C)
 if("${CMAKE_GENERATOR}" MATCHES "Visual Studio 6")
   # VS 6 generator does not use per-target object locations.
   set(vs6 _vs6)