diff --git a/src/util/simple_mtx.h b/src/util/simple_mtx.h
index ab206cebcd8..4152bb681e0 100644
--- a/src/util/simple_mtx.h
+++ b/src/util/simple_mtx.h
@@ -50,10 +50,6 @@
  * condition variables.
  */
 
-typedef struct {
-   uint32_t val;
-} simple_mtx_t;
-
 #ifndef __OPENCL_VERSION__
 
 #include "util/futex.h"
@@ -78,6 +74,9 @@ extern "C" {
 #endif
 
 #if UTIL_FUTEX_SUPPORTED
+typedef struct {
+   uint32_t val;
+} simple_mtx_t;
 
 #define SIMPLE_MTX_INITIALIZER { 0 }
 
@@ -209,6 +208,11 @@ simple_mtx_assert_locked(simple_mtx_t *mtx)
 
 #else
 
+/* Dummy implementation to let more headers compile with OpenCL */
+typedef struct {
+   uint32_t _;
+} simple_mtx_t;
+
 #endif
 
 #endif /* _SIMPLE_MTX_H */