Remove the built-in print and the jerry_port_console port API functions (#1749)

The built-in `print` is removed from jerry-core, but an external
`print` implementation is added to jerry-main. From now on, all
embedders of the engine have to implement their own `print` if they
need such a functionality.

For printing results in REPL mode of jerry-main, the external
`print` handler is called directly instead of looking up the `print`
function registered into the global object. (The two are the same,
but the indirection is not needed anymore.)

Because jerry-core does not contain `print` anymore,
`jerry_port_console` is removed from the port API. The default port
is updated, i.e., the implementation of `jerry_port_console` is
removed. Additionally, all references to `jerry_port_console` in
jerry-main are replaced by `printf`.

Speculatively, `jerry_port_console` is also removed from all
non-default targets. Most targets implemented it for the sake of the
engine only; in those targets the removal was trivial. Where the
function was called from the embedder application as well, the
calls were replaced with equivalents (e.g., `printf`, `printk`).

NOTE 1: This is a breaking change!

NOTE 2: This patch still leaves several targets without a JS `print`
implementation.

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

docs/03.API-EXAMPLE.md

@@ -173,38 +173,38 @@ created by API functions has the error flag set.
 The following example function will output a JavaScript value:
 
 ```c
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "jerryscript.h"
-#include "jerryscript-port.h"
 
 static void
 print_value (const jerry_value_t value)
 {
   if (jerry_value_is_undefined (value))
   {
-    jerry_port_console ("undefined");
+    printf ("undefined");
   }
   else if (jerry_value_is_null (value))
   {
-    jerry_port_console ("null");
+    printf ("null");
   }
   else if (jerry_value_is_boolean (value))
   {
     if (jerry_get_boolean_value (value))
     {
-      jerry_port_console ("true");
+      printf ("true");
     }
     else
     {
-      jerry_port_console ("false");
+      printf ("false");
     }
   }
   /* Float value */
   else if (jerry_value_is_number (value))
   {
-    jerry_port_console ("number");
+    printf ("number");
   }
   /* String value */
   else if (jerry_value_is_string (value))
@@ -216,15 +216,15 @@ print_value (const jerry_value_t value)
     jerry_string_to_char_buffer (value, str_buf_p, req_sz);
     str_buf_p[req_sz] = '\0';
 
-    jerry_port_console ("%s", (const char *) str_buf_p);
+    printf ("%s", (const char *) str_buf_p);
   }
   /* Object reference */
   else if (jerry_value_is_object (value))
   {
-    jerry_port_console ("[JS object]");
+    printf ("[JS object]");
   }
 
-  jerry_port_console ("\n");
+  printf ("\n");
 }
 ```
 
@@ -243,11 +243,11 @@ Shell operation can be described with the following loop:
   - loop.
 
 ```c
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "jerryscript.h"
-#include "jerryscript-port.h"
 
 static void print_value (const jerry_value_t);
 
@@ -265,7 +265,7 @@ main (int argc, char *argv[])
     char *cmd_tail = cmd;
     size_t len = 0;
 
-    jerry_port_console ("> ");
+    printf ("> ");
 
     /* Read next command */
     while (true)
@@ -302,7 +302,7 @@ main (int argc, char *argv[])
     {
       /* Evaluated JS code thrown an exception
        *  and didn't handle it with try-catch-finally */
-      jerry_port_console ("Unhandled JS exception occured: ");
+      printf ("Unhandled JS exception occured: ");
     }
 
     print_value (ret_val);