* add copy_cut_border check; fix compile warnings

* 去掉对stl的依赖

* 头文件名，push_back改正

* 去掉构造托管

* 好像是折腾

* data 的返回改为指针，非指针引用

* resize一处写错

* stdint

* 加入c_str

* 改文件名为小写

* NCNN_SIMPLESTL option

* simplestl default to OFF

* Update linux-x64-cpu-gcc.yml

* Update linux-x64-cpu-gcc.yml

* Update linux-x64-cpu-clang.yml

* drop functional header

* arm32 arm64 simplestl ci

* 修改一处内存泄漏, 去掉编译器警告

* resize时默认量的bug

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

* Add: pi3.toolchain.cmake - CMake variables for Pi3 compilation.

* Modify: CMakeLists.txt - Add definitions for Pi3 compilation.

* Modify: src/cpu.cpp - Use getpid() if -PI3 is used.