Introduce the Termination Port API

* Moved the error codes to jerry-port.h and declared port function
  `jerry_port_fatal`.

* Moved "exit or abort on fail" functionality to the newly added
  jerry-port-default-fatal.c.

* This implied that a default port-specific API had to be introduced:
  functions `jerry_port_default_set_abort_on_fail` and
  `jerry_port_default_is_abort_on_fail` declared in jerry-port-default.h
  control the fatal exit behaviour.

* For the sake of clarity, renamed jerry-port.c to
  jerry-port-default-io.c.

* Adapted CMakeLists to deal with port implementations consisting of
  more then one source file and exposing headers. This also required
  the renaming of `EXTERNAL_PORT_FILE` cmake option to
  `EXTERNAL_PORT_DIR`.

* Adapted main sources to use the default port header for the
  abort-on-fail functionality, as that is not part of the core jerry
  API anymore.

* Added default port implementation to the static source code checker
  tools.

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu

jerry-core/CMakeLists.txt

@@ -148,11 +148,7 @@ project (JerryCore C ASM)
       ${SOURCE_CORE_JRT})
 
  # Jerry port
- if(USE_DEFAULT_PORT)
-   file(GLOB SOURCE_PORT_FILES ${CMAKE_SOURCE_DIR}/targets/default/*.c)
- else()
-   set(SOURCE_PORT_FILES ${SOURCE_PORT_IMPLEMENTATION})
- endif()
+ file(GLOB SOURCE_PORT_FILES ${PORT_DIR}/*.c)
 
  # All-in-one build
  if("${ENABLE_ALL_IN_ONE}" STREQUAL "ON")