misc: Fix a small pile of warnings found with diagnostics turned way up

* possible null pointer dereferences
 * non-annotated fallthroughs in case statements

Change-Id: I2332e0e0a4203ceca0999291ead112b8ab94c613

apps/plugins/calculator.c

@@ -1735,6 +1735,7 @@ static void typingProcess(void){
                         clearOperand();
                     calStatus = cal_typing;
                     /* go on typing, no break */
+                    /* Intentional fallthrough */
                 case cal_typing:
                 case cal_dotted:
                     switch(CAL_BUTTON){

apps/plugins/goban/sgf.c

@@ -1304,7 +1304,7 @@ read_comment_sgf (char *buffer, size_t buffer_size)
             {
                 break;
             }
-
+            /* Intentional fallthrough */
         default:
             *buffer = temp;
             ++buffer;

apps/plugins/goban/sgf_storage.c

@@ -152,6 +152,7 @@ free_tree_sgf (void)
     {
         rb->splash (5 * HZ,
                     "Error allocating first node!  Please exit immediately.");
+        return;
     }
 
     get_node (tree_head)->props = NO_PROP;
@@ -498,4 +499,3 @@ get_prop (int handle)
     }
     return &(storage_buffer[index][handle].prop);
 }
-

apps/plugins/imageviewer/imageviewer.c

@@ -406,6 +406,7 @@ static int ask_and_get_audio_buffer(const char *filename)
                 break;
 #endif
 #endif
+            /* Intentional fallthrough */
             case IMGVIEW_MENU:
                 return PLUGIN_OK;
 

apps/plugins/lastfm_scrobbler_viewer.c

@@ -809,8 +809,7 @@ static int scrobbler_context_menu(struct printcell_data_t *pc_data)
 
                 if (find_type == FIND_ALL)
                     find_type = FIND_INCLUDE;
-                /* fallthrough */
-            }
+            } /* fall-through */
             case 3: /*Custom Filter / Settings */
             {
                 if (col == -1)/*Settings*/

apps/plugins/pdbox/PDa/src/d_ugen.c

@@ -655,7 +655,7 @@ void ugen_connect(t_dspcontext *dc, t_object *x1, int outno, t_object *x2,
     for (u2 = dc->dc_ugenlist; u2 && u2->u_obj != x2; u2 = u2->u_next);
     if (!u1 || !u2 || siginno < 0)
     {
-    	pd_error(u1->u_obj,
+        pd_error((u1 ? u1->u_obj : NULL),
 	    "signal outlet connect to nonsignal inlet (ignored)");
     	return;
     }
@@ -1159,4 +1159,3 @@ void d_ugen_setup(void)  /* really just block_setup */
     class_addmethod(block_class, (t_method)block_dsp, gensym("dsp"), 0);
     class_addfloat(block_class, block_float);
 }
-

apps/plugins/pdbox/PDa/src/m_class.c

@@ -713,6 +713,7 @@ void pd_typedmess(t_pd *x, t_symbol *s, int argc, t_atom *argv)
 		break;
 	    case A_FLOAT:
 		if (!argc) goto badarg;
+                /* Intentional fallthrough */
     	    case A_DEFFLOAT:
     		if (!argc) *dp = 0;
 		else
@@ -727,6 +728,7 @@ void pd_typedmess(t_pd *x, t_symbol *s, int argc, t_atom *argv)
 		break;
 	    case A_SYMBOL:
 		if (!argc) goto badarg;
+                /* Intentional fallthrough */
     	    case A_DEFSYM:
     		if (!argc) *ap = (t_int)(&s_);
     		else
@@ -861,4 +863,3 @@ t_gotfn zgetfn(t_pd *x, t_symbol *s)
 	if (m->me_name == s) return(m->me_fun);
     return(0);
 }
-

apps/plugins/rockboy/mem.c

@@ -269,6 +269,7 @@ static byte ioreg_read(byte r)
     case RI_HDMA4:
     case RI_HDMA5:
         if (hw.cgb) return REG(r);
+        /* Intentional fallthrough */
     default:
         return 0xff;
     }

firmware/target/arm/s5l8702/ipod6g/audio-6g.c

@@ -88,6 +88,7 @@ void audio_input_mux(int source, unsigned flags)
     {
         default:                        /* playback - no recording */
             source = AUDIO_SRC_PLAYBACK;
+            /* Intentional fallthrough */
         case AUDIO_SRC_PLAYBACK:
 #ifdef HAVE_RECORDING
             if (source != last_source)