问题1：
:311:52: error: operator '&&' has no right operand
解决方法：
在/home/jsaon/tool/opencv-3.4.5/3rdparty/protobuf/src/google/protobuf/stubs/ 中添加下面这一行
#define HAVE_PTHREAD
问题2：
/home/tanyd/zdyz/linaro494/arm-linux-gnueabihf/libc/usr/include/:311:52: error: operator '&&' has no right operand
#if defined _FILE_OFFSET_BITS && _FILE_OFFSET_BITS == 64
在#if defined前面 加上
#define _FILE_OFFSET_BITS 64
问题3：
../../lib/libopencv_core.so: undefined reference to `pthread_key_create'
../../lib/libopencv_core.so: undefined reference to `dlsym'
../../lib/libopencv_core.so: undefined reference to `pthread_getspecific'
../../lib/libopencv_core.so: undefined reference to `dladdr'
../../lib/libopencv_core.so: undefined reference to `pthread_key_delete'
../../lib/libopencv_core.so: undefined reference to `dlopen'
../../lib/libopencv_core.so: undefined reference to `pthread_setspecific'
../../lib/libopencv_core.so: undefined reference to `dlclose'
修改目录下的，CMAKE_EXE_LINKER_FLAGS原来为空，加上-lpthread -lrt -ldl
问题4：
error: invalid conversion from ‘uchar* {aka unsigned char*}’ to ‘const JOCTET* {aka const char*}’ [-fpermissive]
解决办法:修改build目录下的,
CMAKE_CXX_FLAGS:STRING=-fpermissive
问题5：
:83:15: error: converting to ‘std::unordered_map<std::basic_string<ch
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