2 files changed, 14 insertions, 0 deletions
diff --git a/Tests/Module/WriteCompilerDetectionHeader/CMakeLists.txt b/Tests/Module/WriteCompilerDetectionHeader/CMakeLists.txt
index 645cc65..7bf9f28 100644
--- a/Tests/Module/WriteCompilerDetectionHeader/CMakeLists.txt
+++ b/Tests/Module/WriteCompilerDetectionHeader/CMakeLists.txt
@@ -63,6 +63,13 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL GNU
   list(APPEND false_defs EXPECTED_COMPILER_CXX_VARIADIC_TEMPLATES)
 endif()
 
+if (CMAKE_C_COMPILER_ID STREQUAL GNU
+    OR CMAKE_C_COMPILER_ID STREQUAL Clang)
+  add_executable(C_undefined c_undefined.c)
+  set_property(TARGET C_undefined PROPERTY CXX_STANDARD 90)
+  target_compile_options(C_undefined PRIVATE -Werror=undef)
+endif()
+
 add_executable(WriteCompilerDetectionHeader main.cpp)
 set_property(TARGET WriteCompilerDetectionHeader PROPERTY CXX_STANDARD 98)
 set_defines(WriteCompilerDetectionHeader "${true_defs}" "${false_defs}")
diff --git a/Tests/Module/WriteCompilerDetectionHeader/c_undefined.c b/Tests/Module/WriteCompilerDetectionHeader/c_undefined.c
new file mode 100644
index 0000000..487e66d
--- /dev/null
+++ b/Tests/Module/WriteCompilerDetectionHeader/c_undefined.c
@@ -0,0 +1,7 @@
+
+#include "test_compiler_detection.h"
+
+int main()
+{
+  return 0;
+}