Work around some clang parsing issues

clang has no problem with labels crossing declarations, but it can't
cope with a declaration (or end of block) just after a label.

libs/gamecode/pr_exec.c

@@ -1797,6 +1797,7 @@ op_call:
 		}
 	}
 exit_program:
+	(void)0;//FIXME for clang
 }
 
 #define MM(type) (*((pr_##type##_t *) (mm)))
@@ -1816,6 +1817,7 @@ pr_address_mode (progs_t *pr, const dstatement_t *st, int mm_ind)
 			break;
 		case 1:
 			// entity.field (equivalent to OP_LOAD_t_v6p)
+			(void)0;//FIXME for clang
 			pr_ptr_t    edict_area = pr->pr_edict_area - pr->pr_globals;
 			mm_offs = edict_area + OPA(entity) + OPB(field);
 			break;
@@ -1853,6 +1855,7 @@ pr_call_mode (progs_t *pr, const dstatement_t *st, int mm_ind)
 			break;
 		case 4:
 			// entity.field (equivalent to OP_LOAD_t_v6p)
+			(void)0;//FIXME for clang
 			pr_ptr_t    edict_area = pr->pr_edict_area - pr->pr_globals;
 			mm_offs = edict_area + OPA(entity) + OPB(field);
 			break;
@@ -2547,6 +2550,7 @@ pr_exec_ruamoko (progs_t *pr, int exitdepth)
 				break;
 			OP_cmp_T (LT, U, long, lvec2, lvec4, <, ulong, ulvec2, ulvec4);
 			case OP_RETURN:
+				(void)0;//FIXME for clang
 				int         ret_size = (st->c & 0x1f) + 1;	// up to 32 words
 				if (st->c != 0xffff) {
 					mm = pr_address_mode (pr, st, st->c >> 5);
@@ -2872,6 +2876,7 @@ pr_exec_ruamoko (progs_t *pr, int exitdepth)
 		}
 	}
 exit_program:
+	(void)0;//FIXME for clang
 }
 /*
 	PR_ExecuteProgram

libs/gamecode/test/main.c

@@ -42,6 +42,7 @@ test_debug_handler (prdebug_t event, void *param, void *data)
 		case prd_subexit:
 			break;
 		case prd_trace:
+			(void)0;//FIXME for clang
 			dstatement_t *st = test_pr.pr_statements + test_pr.pr_xstatement;
 			if (verbose > 1) {
 				printf ("---\n");

libs/video/renderer/r_efrag.c

@@ -237,8 +237,8 @@ R_StoreEfrags (const efrag_t *efrag)
 			case mod_iqm:
 				EntQueue_AddEntity (r_ent_queue, ent, model->type);
 				break;
-
 			default:
+				(void)0;//FIXME for clang
 		}
 		efrag = efrag->leafnext;
 	}