fix clang compile opencl. test=develop (#3153)

cmake/cross_compiling/postproject.cmake

@@ -59,7 +59,7 @@ function(check_linker_flag)
 endfunction()
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
 if (LITE_ON_TINY_PUBLISH)
-    if(NOT LITE_WITH_PYTHON)
+    if((NOT LITE_WITH_PYTHON) AND (NOT LITE_WITH_OPENCL))
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-exceptions")
     endif()
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -ffast-math -Ofast -Os -fomit-frame-pointer -fno-asynchronous-unwind-tables -fno-unwind-tables")