bme280_math Lua 5.3 compatibility issue with lua_pushfstring

Author: vsky

app/modules/bme280_math.c

@@ -246,12 +246,16 @@ int bme280_lua_setup(lua_State* L) {
 #undef r16sLE_buf
 
   int i = 1;
+  char cfg[2]={'\0', '\0'};
   lua_newtable(L);  /* configuration table */
-  lua_pushfstring(L, "%c", config);
+  cfg[0]=(char)config;
+  lua_pushstring(L, cfg);
   lua_rawseti(L, -2, i++);
-  lua_pushfstring(L, "%c", bme280_ossh);
+  cfg[0]=(char)bme280_ossh;
+  lua_pushstring(L, cfg);
   lua_rawseti(L, -2, i++);
-  lua_pushfstring(L, "%c", bme280_mode);
+  cfg[0]=(char)bme280_mode;
+  lua_pushstring(L, cfg);
   lua_rawseti(L, -2, i);
   return 2;
 }