For older cmake, a second-tier test to detect if we're using clang
For older cmake, a second-tier test to detect if we're using clang

scott-wilson/oiio,sambler/oiio,scott-wilson/oiio,lgritz/oiio,OpenImageIO/oiio,bdeluca/oiio,OpenImageIO/oiio,YangYangTL/oiio,bdeluca/oiio,scott-wilson/oiio,mcanthony/oiio,YangYangTL/oiio,lgritz/oiio,micler/oiio,OpenImageIO/oiio,bdeluca/oiio,cwilling/oiio,lgritz/oiio,micler/oiio,cwilling/oiio,YangYangTL/oiio,micler/oiio,sambler/oiio,mcanthony/oiio,scott-wilson/oiio,sambler/oiio,bdeluca/oiio,OpenImageIO/oiio,cwilling/oiio,mcanthony/oiio,lgritz/oiio,sambler/oiio,mcanthony/oiio,YangYangTL/oiio,micler/oiio,cwilling/oiio