* fix darknet2ncnn.cpp warnings

* revoke extra warning check

* fix cmake 3.5.1 config error

* fix ubuntu16.04 build error

* vulkan cmake export templete

* 1) vulkan cmake dependency export. 2) support opencv_world import. 3) add BUILD_WITH_STATIC_CRT option

* Threads dependency

* NCNN_BUILD_WITH_STATIC_CRT option

* we do not support cmake before version 3.15 for option NCNN_BUILD_WITH_STATIC_CRT

* fix maxpool padding size

* restyle

* fix #1941 darknet2ncnn maxpool out_w issue

* fix typo caused build fail

* fix opencv4 c++11 flags in example folder

* fix #1542; fix avx2 uint16_t including

for #1542, it is for compatibility for opencv 2.x, such as on ubuntu 16.04 apt installed opencv

* Add yolov4 example option.
Add yolov4-tiny for benchmark.

* Restyled by astyle

* Restyled by clang-format

* Restyled by astyle

Co-authored-by: Restyled.io <commits@restyled.io>

* tf2sb

* wip

* wip

* concat maxpool avgpool

* StridedSlice

* handle stridedslice mask

* convert mlir deconvolution

* convert deconvolution output shape

* convert tanh

* code format

* Support yolov4-tiny conversion.
Add darknet2ncnn readme.
Add yolov4 example.

* Restyled by clang-format

* Restyled by astyle

* Restyled by clang-format

* Restyled by astyle

Co-authored-by: Restyled.io <commits@restyled.io>

* update roialign

* update tool for roialign

* fix ceil for roialign

* fix ios build

* fix

* fix

* make it compatibile with the old version

* fix ios build

* trigger CI

* fix test

* order

* build

* remove code

* merge roialign

* accelerate ROIAlign

* update note

* rename func

* roialign version

* trigger CI

* fix roialign

* use ref for pre-calc in roialign

* retrigger CI

* pre-alloc