OSX/clang: Fix T41123, crashing osl when optimization level > O0 is used for osl_shaders.cpp
OSX/clang: Fix T41123, crashing osl when optimization level > O0 is used for osl_shaders.cpp

tangent-opensource/coreBlackbird,tangent-opensource/coreBlackbird,tangent-opensource/coreBlackbird,pyrochlore/cycles,pyrochlore/cycles,pyrochlore/cycles