Cycles: Fix compilation with older OSL

We didn't switch to OSL-1.6.9 on all platforms yet,
so please keep codeabse compiled with 1.5 for the
time being.

intern/cycles/render/osl.cpp

@@ -282,7 +282,11 @@ bool OSLShaderManager::osl_compile(const string& inputfile, const string& output
 	stdosl_path = path_get("shader/stdosl.h");
 
 	/* compile */
+#if OSL_LIBRARY_VERSION_CODE >= 10602
 	OSL::OSLCompiler *compiler = new OSL::OSLCompiler(&OSL::ErrorHandler::default_handler());
+#else
+	OSL::OSLCompiler *compiler = new OSL::OSLCompiler();
+#endif
 	bool ok = compiler->compile(string_view(inputfile), options, string_view(stdosl_path));
 	delete compiler;