Cycles: Fix building with native only option

Approach suggested by Lukas S.

intern/cycles/kernel/kernels/cpu/kernel_cpu_impl.h

@@ -22,7 +22,8 @@
 
 #include "kernel/kernel_compat_cpu.h"
 
-#ifndef __SPLIT_KERNEL__
+#ifndef KERNEL_STUB
+#  ifndef __SPLIT_KERNEL__
 #    include "kernel/kernel_math.h"
 #    include "kernel/kernel_types.h"
 
@@ -34,7 +35,7 @@
 #    include "kernel/kernel_path.h"
 #    include "kernel/kernel_path_branched.h"
 #    include "kernel/kernel_bake.h"
-#else
+#  else
 #    include "kernel/split/kernel_split_common.h"
 
 #    include "kernel/split/kernel_data_init.h"
@@ -55,12 +56,15 @@
 #    include "kernel/split/kernel_next_iteration_setup.h"
 #    include "kernel/split/kernel_indirect_subsurface.h"
 #    include "kernel/split/kernel_buffer_update.h"
-#endif
-
-#ifdef KERNEL_STUB
+#  endif  /* __SPLIT_KERNEL__ */
+#else
 #  include "util/util_debug.h"
 #  define STUB_ASSERT(arch, name) assert(!(#name " kernel stub for architecture " #arch " was called!"))
-#endif
+
+#  ifdef __SPLIT_KERNEL__
+#    include "kernel/split/kernel_data_init.h"
+#  endif  /* __SPLIT_KERNEL__ */
+#endif  /* KERNEL_STUB */
 
 CCL_NAMESPACE_BEGIN
 
@@ -191,20 +195,26 @@ void KERNEL_FUNCTION_FULL_NAME(shader)(KernelGlobals *kg,
 	{ \
 		STUB_ASSERT(KERNEL_ARCH, name); \
 	}
+
+#  define DEFINE_SPLIT_KERNEL_FUNCTION_LOCALS(name, type) \
+	void KERNEL_FUNCTION_FULL_NAME(name)(KernelGlobals *kg, KernelData* /*data*/) \
+	{ \
+		STUB_ASSERT(KERNEL_ARCH, name); \
+	}
 #else
 #  define DEFINE_SPLIT_KERNEL_FUNCTION(name) \
 	void KERNEL_FUNCTION_FULL_NAME(name)(KernelGlobals *kg, KernelData* /*data*/) \
 	{ \
 		kernel_##name(kg); \
 	}
-#endif /* KERNEL_STUB */
 
-#define DEFINE_SPLIT_KERNEL_FUNCTION_LOCALS(name, type) \
+#  define DEFINE_SPLIT_KERNEL_FUNCTION_LOCALS(name, type) \
 	void KERNEL_FUNCTION_FULL_NAME(name)(KernelGlobals *kg, KernelData* /*data*/) \
 	{ \
 		ccl_local type locals; \
 		kernel_##name(kg, &locals); \
 	}
+#endif /* KERNEL_STUB */
 
 DEFINE_SPLIT_KERNEL_FUNCTION(path_init)
 DEFINE_SPLIT_KERNEL_FUNCTION(scene_intersect)

intern/cycles/kernel/split/kernel_data_init.h

@@ -67,6 +67,10 @@ void KERNEL_FUNCTION_FULL_NAME(data_init)(
         unsigned int num_samples,
         ccl_global float *buffer)
 {
+#ifdef KERNEL_STUB
+	STUB_ASSERT(KERNEL_ARCH, data_init);
+#else
+
 #ifdef __KERNEL_OPENCL__
 	kg->data = data;
 #endif
@@ -143,6 +147,8 @@ void KERNEL_FUNCTION_FULL_NAME(data_init)(
 			*(rng_state + index) = hash_int_2d(x, y);
 		}
 	}
+
+#endif  /* KERENL_STUB */
 }
 
 CCL_NAMESPACE_END