[openssl] CMake not able to find OpenSSL library

If you can use pkg-config: pkg_search_module() can find OpenSSL for you.

# Search OpenSSL
find_package(PkgConfig REQUIRED)
pkg_search_module(OPENSSL REQUIRED openssl)

if( OPENSSL_FOUND )
    include_directories(${OPENSSL_INCLUDE_DIRS})
    message(STATUS "Using OpenSSL ${OPENSSL_VERSION}")
else()
    # Error; with REQUIRED, pkg_search_module() will throw an error by it's own
endif()

target_link_libraries(${YOUR_TARGET_HERE} ${OPENSSL_LIBRARIES})