crash when freeing a ncnn dynamic library

* Fixed compile warnings for gcc linux gpu 64 build. [-Wunused-parameter]

* Fixed linux x64 gpu clang compile warning. [-Wunused-variable]

* fix packing.cpp integer multiply may overflow

* int->size_t

* fix darknet2ncnn.cpp warnings

* revoke extra warning check

* fix -Wmaybe-uninitialized

build warning: ‘_outh’ '_outw'  may be used uninitialized

* Restyled by clang-format

* Restyled by astyle

* Restyled by clang-format

* Restyled by astyle

Co-authored-by: ncnnnnn <67086033+ncnnnnn@users.noreply.github.com>
Co-authored-by: Restyled.io <commits@restyled.io>

* reset

* fix build with old vulkan header

* query subgroup features

* compile spirv 1.3

* drop offline spirv build

* do not build tests for android and ios, as they are never tested anyway

* code style

* Improve build instructions

* Merge Linux stuff into one section.
* Provide better info on dependencies
* Provide easier to use instruction for Debian / Ubuntu for native and cross-compile builds
* Capitalize Sentence and put proper punctation.
* Use backticks where appropiate
* Move Hisilicon instruction together with Arm crosscompiling
* Add information how to verify the Vulkan installation on Linux
* Change how to launch examples so it is easier (no copying needed or external resources)
* Add info about benchmark and how to test it on GPU or CPU
* Use `$(nproc)` where appropriate.
* Put some paths in quotes, in case they contain spaces or other weird characters (coma, semicolon, colon, etc).
* Remove some extremely obvious pieces that every developer usually knows.
* Use newer Vulkan SDK in instructions for Linux
* Get rid of `<ncnn-root-dir>`, and just use `ncnn`. It is what git clone does. And any developer will know how to change it if they choose to do it differently.

* Update README.md

* Update how-to-build.md

Co-authored-by: nihui <shuizhuyuanluo@126.com>

* softplus inplace

* softplus inplace add src/tests CMakeLists.txt

* Update CMakeLists.txt

* Update softplus.cpp

* Update softplus.h

* Update softplus.cpp

* Update test_softplus.cpp

* Update softplus.cpp

* Update softplus.h

Co-authored-by: sf <sf@sf.sf>
Co-authored-by: nihui <shuizhuyuanluo@126.com>

Co-authored-by: nihui <shuizhuyuanluo@126.com>