feat: implement proxy jump using libssh

tests: modify proxyjump tests to check for ssh_jump_info_struct

tests: add proxyjump functionality test

feat: add SSH_OPTIONS_PROXYJUMP

tests: proxyjump, check authentication

fix: ssh_socket_connect_proxyjump add exit label to exit on error

feat: implement io forwarding using pthread

feat: proxyjump: use threading instead of forking

feat: proxyjump: cancel forwarding threads on ssh_disconnect

fix: proxyjump remove ProxyJump bool and put pthread ifdefs

feat: use ssh_event for io forwarding instead of threads

reformat: tests to use assert_int_not_equal

fix: link to pthread

refactor: make function to free proxy jump list

docs: add comment for proxy jump channel

feat: add env variable to enable libssh proxy jump

feat: open channel for proxyjump like OpenSSH

feat: add more tests for proxy jump

fix: use a global variable to close io forwarding, this prevents segfaults

fix: handle proxy list in thread without creating copy
Signed-off-by: Gauravsingh Sisodia <xaerru@gmail.com>
Reviewed-by: Jakub Jelen <jjelen@redhat.com>
Reviewed-by: Eshan Kelkar <eshankelkar@galorithm.com>

tests/fuzz/CMakeLists.txt

@@ -4,7 +4,7 @@ macro(fuzzer name)
     add_executable(${name} ${name}.c)
     target_link_libraries(${name}
                           PRIVATE
-                              ssh::static)
+                              ssh::static pthread)
     if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
         set_target_properties(${name}
                               PROPERTIES