compile warning help: 'WIN32_LEAN_AND_MEAN': macro redefinition & 'ncnn::create_gpu_instance': inconsistent dll linkage

[Roger8]

I use ncnn lib in my project , warnings come while compiling , how to resolve the problem ?
1. I dont need gpu api ,may i need to rebuild ncnn lib without gpu settings.

os: windows 10 msvc 2019

\ncnn\allocator.h(19,1): warning C4005: 'WIN32_LEAN_AND_MEAN': macro redefinition 
vision\xxx.cpp : message : see previous definition of 'WIN32_LEAN_AND_MEAN'
ncnn\blob.h(32,17): warning C4251: 'ncnn::Blob::name': class 'std::basic_string<char,std::char_traits<char>,std::allocator<char>>' needs to have dll-interface to be used by clients of class 'ncnn::Blob' 
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\include\xstring(4871): message : see declaration of 'std::basic_string<char,std::char_traits<char>,std::allocator<char>>' 
ncnn\gpu.h(315,60): warning C4273: 'ncnn::create_gpu_instance': inconsistent dll linkage 
\gpu.h(32,17): message : see previous definition of 'create_gpu_instance' 
layer.h(148,17): warning C4251: 'ncnn::Layer::type': class 'std::basic_string<char,std::char_traits<char>,std::allocator<char>>' needs to have dll-interface to be used by clients of class 'ncnn::Layer' 
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\include\xstring(4871): message : see declaration of 'std::basic_string<char,std::char_traits<char>,std::allocator<char>>' 
layer.h(150,17): warning C4251: 'ncnn::Layer::name': class 'std::basic_string<char,std::char_traits<char>,std::allocator<char>>' needs to have dll-interface to be used by clients of class 'ncnn::Layer' 
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\include\xstring(4871): message : see declaration of 'std::basic_string<char,std::char_traits<char>,std::allocator<char>>' 
layer.h(153,22): warning C4251: 'ncnn::Layer::bottoms': class 'std::vector<int,std::allocator<int>>' needs to have dll-interface to be used by clients of class 'ncnn::Layer' 
include\opencv2\core\types.hpp(749): message : see declaration of 'std::vector<int,std::allocator<int>>' 
layer.h(155,22): warning C4251: 'ncnn::Layer::tops': class 'std::vector<int,std::allocator<int>>' needs to have dll-interface to be used by clients of class 'ncnn::Layer' 
include\opencv2\core\types.hpp(749): message : see declaration of 'std::vector<int,std::allocator<int>>' 
layer.h(157,22): warning C4251: 'ncnn::Layer::bottom_shapes': class 'std::vector<ncnn::Mat,std::allocator<ncnn::Mat>>' needs to have dll-interface to be used by clients of class 'ncnn::Layer' 
layer.h(102): message : see declaration of 'std::vector<ncnn::Mat,std::allocator<ncnn::Mat>>' 
layer.h(158,22): warning C4251: 'ncnn::Layer::top_shapes': class 'std::vector<ncnn::Mat,std::allocator<ncnn::Mat>>' needs to have dll-interface to be used by clients of class 'ncnn::Layer' 
layer.h(102): message : see declaration of 'std::vector<ncnn::Mat,std::allocator<ncnn::Mat>>' 
allocator.h(19,1): warning C4005: 'WIN32_LEAN_AND_MEAN': macro redefinition 
`xxxx.cpp` : message : see previous definition of 'WIN32_LEAN_AND_MEAN'
gpu.h(315,60): warning C4273: 'ncnn::create_gpu_instance': inconsistent dll linkage (
gpu.h(32,17): message : see previous definition of 'create_gpu_instance' 

[Roger8]

resolved :

1. 'create_gpu_instance' warning. (rebuild ncnn by disable vulkan =false)
2. 'WIN32_LEAN_AND_MEAN' warning.( comment the line define)
   still warning:
3. ncnn\blob.h(32,17): warning C4251: 'ncnn::Blob::name': class 'std::basic_string<char,std::char_traits,std::allocator>' needs to have dll-interface to be used by clients of class 'ncnn::Blob'
   C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30133\include\xstring(4871): message : see declaration of 'std::basic_string<char,std::char_traits,std::allocator>'

layer.h(158,22): warning C4251: 'ncnn::Layer::top_shapes': class 'std::vector<ncnn::Mat,std::allocatorncnn::Mat>' needs to have dll-interface to be used by clients of class 'ncnn::Layer'
layer.h(102): message : see declaration of 'std::vector<ncnn::Mat,std::allocatorncnn::Mat>'