Add ssl subdirectory in your repo.
git submodule add https://github.com/zhaojh329/ssl.git
Add these code in the CMakeLists.txt of your repo.
add_subdirectory(ssl)
if(SSL_SUPPORT)
target_link_libraries(xx PRIVATE ${SSL_TARGET})
endif()
Include ssl.h in your source code.
#ifdef SSL_SUPPORT
#include "ssl/ssl.h"
#endif
// SSL support
SSL_SUPPORT:BOOL
// Force select MbedTLS(PolarSSL)
USE_MBEDTLS:BOOL
// Force select OpenSSL
USE_OPENSSL:BOOL
// Force select WolfSSL(CyaSSL)
USE_WOLFSSL:BOOL