enable online spirv by default

CMakeLists.txt

@@ -30,7 +30,7 @@ option(NCNN_PIXEL "convert and resize from/to image pixel" ON)
 option(NCNN_PIXEL_ROTATE "rotate image pixel orientation" ON)
 option(NCNN_CMAKE_VERBOSE "print verbose cmake messages" OFF)
 option(NCNN_VULKAN "vulkan compute support" OFF)
-option(NCNN_VULKAN_ONLINE_SPIRV "online SPIR-V module compilation" OFF)
+option(NCNN_VULKAN_ONLINE_SPIRV "online SPIR-V module compilation" ON)
 option(NCNN_REQUANT "auto merge int8 quant and dequant" OFF)
 option(NCNN_AVX2 "optimize x86 platform with avx2" OFF)
 option(NCNN_DISABLE_PIC "disable position-independent code" OFF)
@@ -65,7 +65,7 @@ if(NCNN_COVERAGE)
     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -coverage -lgcov")
 endif()
 
-if(NCNN_VULKAN_ONLINE_SPIRV)
+if(NCNN_VULKAN AND NCNN_VULKAN_ONLINE_SPIRV)
     if(NOT EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/glslang/CMakeLists.txt")
         message(WARNING "The submodules were not downloaded! NCNN_VULKAN_ONLINE_SPIRV will be turned off.")
         message(WARNING "Please update submodules with \"git submodule update --init\" and try again.")