Fix handling of Return and keypad Enter.

The recent rewriting in both the GTK and Windows keyboard handlers
left the keypad 'Enter' key in a bad state, when no override is
enabled that causes it to generate an escape sequence.

On Windows, a series of fallbacks was causing it to generate \r
regardless of configuration, whereas in Telnet mode it should default
to generating the special Telnet new-line sequence, and in response to
ESC[20h (enabling term->cr_lf_return) it should generate \r\n.

On GTK, it wasn't generating anything _at all_, and also, I can't see
any evidence that the GTK keyboard handler had ever remembered to
implement the cr_lf_return mode.

Now Keypad Enter in non-escape-sequence mode should behave just like
Return, on both platforms.

unix/gtkwin.c

@@ -993,6 +993,32 @@ char *dup_keyval_name(guint keyval)
 static void change_font_size(GtkFrontend *inst, int increment);
 static void key_pressed(GtkFrontend *inst);
 
+/* Subroutine used in key_event */
+static int return_key(GtkFrontend *inst, char *output, bool *special)
+{
+    int end;
+
+    /* Ugly label so we can come here as a fallback from
+     * numeric keypad Enter handling */
+    if (inst->term->cr_lf_return) {
+#ifdef KEY_EVENT_DIAGNOSTICS
+        debug(" - Return in cr_lf_return mode, translating as 0d 0a\n");
+#endif
+        output[1] = '\015';
+        output[2] = '\012';
+        end = 3;
+    } else {
+#ifdef KEY_EVENT_DIAGNOSTICS
+        debug(" - Return special case, translating as 0d + special\n");
+#endif
+        output[1] = '\015';
+        end = 2;
+        *special = true;
+    }
+
+    return end;
+}
+
 gint key_event(GtkWidget *widget, GdkEventKey *event, gpointer data)
 {
     GtkFrontend *inst = (GtkFrontend *)data;
@@ -1688,13 +1714,8 @@ gint key_event(GtkWidget *widget, GdkEventKey *event, gpointer data)
 	/* We handle Return ourselves, because it needs to be flagged as
 	 * special to ldisc. */
 	if (event->keyval == GDK_KEY_Return) {
-#ifdef KEY_EVENT_DIAGNOSTICS
-            debug(" - Return special case, translating as 0d + special\n");
-#endif
-	    output[1] = '\015';
-	    use_ucsoutput = false;
-	    end = 2;
-	    special = true;
+            end = return_key(inst, output, &special);
+            use_ucsoutput = false;
 	}
 
 	/* Control-2, Control-Space and Control-@ are NUL */
@@ -1870,6 +1891,15 @@ gint key_event(GtkWidget *widget, GdkEventKey *event, gpointer data)
 #ifdef KEY_EVENT_DIAGNOSTICS
             debug(" - numeric keypad key");
 #endif
+
+            if (end == 1 && num_keypad_key == '\r') {
+                /* Keypad Enter, lacking any other translation,
+                 * becomes the same special Return code as normal
+                 * Return. */
+                end = return_key(inst, output, &special);
+                use_ucsoutput = false;
+            }
+
             use_ucsoutput = false;
             goto done;
 	}

windows/window.c

@@ -4114,6 +4114,7 @@ static int TranslateKey(UINT message, WPARAM wParam, LPARAM lParam,
     bool no_applic_k = conf_get_bool(conf, CONF_no_applic_k);
     bool ctrlaltkeys = conf_get_bool(conf, CONF_ctrlaltkeys);
     bool nethack_keypad = conf_get_bool(conf, CONF_nethack_keypad);
+    char keypad_key = '\0';
 
     HKL kbd_layout = GetKeyboardLayout(0);
 
@@ -4479,14 +4480,8 @@ static int TranslateKey(UINT message, WPARAM wParam, LPARAM lParam,
 	    *p++ = 0x1E;	       /* Ctrl-~ == Ctrl-^ in xterm at least */
 	    return p - output;
 	}
-	if (shift_state == 0 && wParam == VK_RETURN && term->cr_lf_return) {
-	    *p++ = '\r';
-	    *p++ = '\n';
-	    return p - output;
-	}
 
 	switch (wParam) {
-            char keypad_key;
           case VK_NUMPAD0: keypad_key = '0'; goto numeric_keypad;
           case VK_NUMPAD1: keypad_key = '1'; goto numeric_keypad;
           case VK_NUMPAD2: keypad_key = '2'; goto numeric_keypad;
@@ -4520,7 +4515,8 @@ static int TranslateKey(UINT message, WPARAM wParam, LPARAM lParam,
                     (char *)p, term, keypad_key,
                     shift_state & 1, shift_state & 2);
                 if (!nchars) {
-                    /* If we didn't get an escape sequence out of the
+                    /*
+                     * If we didn't get an escape sequence out of the
                      * numeric keypad key, then that must be because
                      * we're in Num Lock mode without application
                      * keypad enabled. In that situation we leave this
@@ -4528,7 +4524,16 @@ static int TranslateKey(UINT message, WPARAM wParam, LPARAM lParam,
                      * below, which will translate it according to the
                      * appropriate keypad layout (e.g. so that what a
                      * Brit thinks of as keypad '.' can become ',' in
-                     * the German layout). */
+                     * the German layout).
+                     *
+                     * An exception is the keypad Return key: if we
+                     * didn't get an escape sequence for that, we
+                     * treat it like ordinary Return, taking into
+                     * account Telnet special new line codes and
+                     * config options.
+                     */
+                    if (keypad_key == '\r')
+                        goto ordinary_return_key;
                     break;
                 }
 
@@ -4592,9 +4597,16 @@ static int TranslateKey(UINT message, WPARAM wParam, LPARAM lParam,
                 keypad_key = '\r';
                 goto numeric_keypad;
             }
-	    *p++ = 0x0D;
-	    *p++ = 0;
-	    return -2;
+          ordinary_return_key:
+            if (shift_state == 0 && term->cr_lf_return) {
+                *p++ = '\r';
+                *p++ = '\n';
+                return p - output;
+            } else {
+                *p++ = 0x0D;
+                *p++ = 0;
+                return -2;
+            }
 	}
     }