FS#13431: Provide a way to view the rockbox license in the menus

This adds a "Legal Notices" entry under the System menu that will
launch the text viewer plugin to display:

1) COPYING.txt   (containing the GPLv2 overall license for Rockbox)
2) LICENSES.txt  (containing all other relevant licenses and notices)

Change-Id: Id41ae491b6f9a6ec5663090246d0f6b661cddea5

3 files changed, 41 insertions, 1 deletions

diff --git a/apps/lang/english-us.lang b/apps/lang/english-us.lang
index 586dc80914..680b3e0883 100644
--- a/apps/lang/english-us.lang
+++ b/apps/lang/english-us.lang
@@ -16298,3 +16298,17 @@
     *: "Always 1"
   </voice>
 </phrase>
+<phrase>
+  id: LANG_LEGAL_NOTICES
+  desc: in system menu
+  user: core
+  <source>
+    *: "Legal Notices"
+  </source>
+  <dest>
+    *: "Legal Notices"
+  </dest>
+  <voice>
+    *: "Legal Notices"
+  </voice>
+</phrase>
diff --git a/apps/lang/english.lang b/apps/lang/english.lang
index fdedf01866..a93cff90ec 100644
--- a/apps/lang/english.lang
+++ b/apps/lang/english.lang
@@ -16374,3 +16374,17 @@
     *: "Always 1"
   </voice>
 </phrase>
+<phrase>
+  id: LANG_LEGAL_NOTICES
+  desc: in system menu
+  user: core
+  <source>
+    *: "Legal Notices"
+  </source>
+  <dest>
+    *: "Legal Notices"
+  </dest>
+  <voice>
+    *: "Legal Notices"
+  </voice>
+</phrase>
diff --git a/apps/menus/main_menu.c b/apps/menus/main_menu.c
index 73c9f7be33..a483a72eb0 100644
--- a/apps/menus/main_menu.c
+++ b/apps/menus/main_menu.c
@@ -121,6 +121,15 @@ static int show_credits(void)
     return 0;
 }
 
+static int show_legal(void)
+{
+    if (plugin_load(VIEWERS_DIR "/text_viewer.rock", "/.rockbox/docs/COPYING.txt") != PLUGIN_OK)
+        show_info();
+    if (plugin_load(VIEWERS_DIR "/text_viewer.rock", "/.rockbox/docs/LICENSES.txt") != PLUGIN_OK)
+        show_info();
+    return 0;
+}
+
 #define SIZE_FMT "%s %s"
 struct info_data
 
@@ -469,9 +478,12 @@ MENUITEM_FUNCTION(show_runtime_item, 0, ID2P(LANG_RUNNING_TIME),
 MENUITEM_FUNCTION(debug_menu_item, 0, ID2P(LANG_DEBUG),
                   debug_menu, NULL, Icon_NOICON);
 
+MENUITEM_FUNCTION(show_legal_item, 0, ID2P(LANG_LEGAL_NOTICES),
+                  show_legal, NULL, Icon_NOICON);
+
 MAKE_MENU(info_menu, ID2P(LANG_SYSTEM), 0, Icon_System_menu,
           &show_info_item, &show_credits_item,
-          &show_runtime_item, &debug_menu_item);
+          &show_runtime_item, &show_legal_item, &debug_menu_item);
 /*      INFO MENU                  */
 /***********************************/