AP_Scripting: prevent a code path to abort() in scripting

if scripting can't find an error handler it can call abort(). We don't
ever want to do that in ArduPilot

libraries/AP_Scripting/lua/src/ldo.c

@@ -128,7 +128,7 @@ l_noret luaD_throw (lua_State *L, int errcode) {
         lua_unlock(L);
         g->panic(L);  /* call panic function (last chance to jump out) */
       }
-      abort();
+      lua_abort();
     }
   }
 }

libraries/AP_Scripting/lua_bindings.cpp

@@ -956,4 +956,23 @@ int lua_range_finder_handle_script_msg(lua_State *L) {
 }
 #endif
 
+/*
+  lua wants to abort, and doesn't have access to a panic function
+ */
+void lua_abort()
+{
+    INTERNAL_ERROR(AP_InternalError::error_t::flow_of_control);
+#if AP_SIM_ENABLED
+    AP_HAL::panic("lua_abort called");
+#else
+    if (!hal.util->get_soft_armed()) {
+        AP_HAL::panic("lua_abort called");
+    }
+    // abort while flying, all we can do is loop
+    while (true) {
+        hal.scheduler->delay(1000);
+    }
+#endif
+}
+
 #endif  // AP_SCRIPTING_ENABLED

libraries/AP_Scripting/lua_common_defs.h

@@ -27,3 +27,5 @@
 #endif // REPL_OUT
 
 int lua_get_current_ref();
+void lua_abort(void) __attribute__((noreturn));
+