Fix layering violation in applications

Apps that use jerry should not (must not!) include and rely on its
internal headers. Typical issue is the use of "jrt/jrt.h". Fixing
`main-{unix,mcu}.c`, and speculatively the apps under the `targets`
directory as well.

(Note: a fix can be either including "jerry-port.h" and using
functions declared there, e.g., `jerry_port_errormsg`, or simply
using standard libc function like `printf`. Both approaches occur
in this patch.)

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

targets/esp8266/source/jerry_extapi.c

@@ -17,7 +17,6 @@
 #include <stdio.h>
 
 #include "jerry-core/jerry.h"
-#include "jerry-core/jrt/jrt.h"  /* for JERRY_ERROR_MSG */
 #include "jerry_extapi.h"
 
 #include "native_esp8266.h"
@@ -52,7 +51,7 @@ DELCARE_HANDLER(assert) {
     printf (">> Jerry assert true\r\n");
     return true;
   }
-  JERRY_ERROR_MSG ("Script assertion failed\n");
+  printf ("Script assertion failed\n");
   exit (JERRY_STANDALONE_EXIT_CODE_FAIL);
   return false;
 }