SWDEV-256292 - Fix build failure when using lightning to build

clang complains there are multiple definitions of ret_val

Change-Id: I949af23e0658b28b339b378c9c0e4681d83d5f5a

opencl/khronos/icd/test/loader_test/test_program_objects.c

@@ -7,7 +7,7 @@ extern cl_program program;
 extern cl_platform_id platform;
 extern cl_device_id devices;
 
-int ret_val;
+static int ret_val;
 
 extern void CL_CALLBACK program_callback(cl_program _a, void* _b);