Turned off clang warnings in third party includes.

The latest clang compiler (at least the one in Xcode 9.4.1) warns about the register keyword and macro expansions using defined().
Since these warnings come from third party code, we can't address them directly in Blender. Silencing them via #pramgas will
at least keep the warnings during a build down to the ones that are relevant to Blender code.

intern/cycles/device/device_cpu.cpp

@@ -21,7 +21,10 @@
 #ifdef WITH_OSL
 /* So no context pollution happens from indirectly included windows.h */
 #  include "util/util_windows.h"
+#  pragma clang diagnostic push
+#  pragma clang diagnostic ignored "-Wdeprecated-register"
 #  include <OSL/oslexec.h>
+#  pragma clang diagnostic pop
 #endif
 
 #include "device/device.h"

intern/cycles/kernel/osl/osl_closures.cpp

@@ -30,8 +30,12 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-register"
+#pragma clang diagnostic ignored "-Wexpansion-to-defined"
 #include <OSL/genclosure.h>
 #include <OSL/oslclosure.h>
+#pragma clang diagnostic pop
 
 #include "kernel/osl/osl_closures.h"
 #include "kernel/osl/osl_shader.h"

intern/cycles/kernel/osl/osl_shader.cpp

@@ -14,7 +14,10 @@
  * limitations under the License.
  */
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-register"
 #include <OSL/oslexec.h>
+#pragma clang diagnostic pop
 
 #include "kernel/kernel_compat_cpu.h"
 #include "kernel/kernel_montecarlo.h"

intern/cycles/render/shader.h

@@ -20,7 +20,10 @@
 #ifdef WITH_OSL
 /* So no context pollution happens from indirectly included windows.h */
 #  include "util/util_windows.h"
+#  pragma clang diagnostic push
+#  pragma clang diagnostic ignored "-Wdeprecated-register"
 #  include <OSL/oslexec.h>
+#  pragma clang diagnostic pop
 #endif
 
 #include "render/attribute.h"

intern/cycles/util/util_image.h

@@ -19,7 +19,11 @@
 
 /* OpenImageIO is used for all image file reading and writing. */
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-register"
+#pragma clang diagnostic ignored "-Wexpansion-to-defined"
 #include <OpenImageIO/imageio.h>
+#pragma clang diagnostic pop
 
 #include "util/util_vector.h"
 

intern/cycles/util/util_param.h

@@ -20,9 +20,13 @@
 /* Parameter value lists from OpenImageIO are used to store custom properties
  * on various data, which can then later be used in shaders. */
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-register"
+#pragma clang diagnostic ignored "-Wexpansion-to-defined"
 #include <OpenImageIO/paramlist.h>
 #include <OpenImageIO/typedesc.h>
 #include <OpenImageIO/ustring.h>
+#pragma clang diagnostic pop
 
 CCL_NAMESPACE_BEGIN
 

source/blender/imbuf/intern/openexr/openexr_api.cpp

@@ -40,6 +40,9 @@
 #include <algorithm>
 #include <iostream>
 
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-register"
 #include <half.h>
 #include <Iex.h>
 #include <ImfVersion.h>
@@ -64,6 +67,7 @@
 #include <ImfTiledOutputPart.h>
 #include <ImfPartType.h>
 #include <ImfPartHelper.h>
+#pragma clang diagnostic pop
 
 #include "DNA_scene_types.h" /* For OpenEXR compression constants */