Compile Mongoose Library with ESP RTOS

#1
  1. My goal is:
    I’m currently working on ESP8266 with espressif’s official ESP8266_RTOS_SDK. I want to use Mongoose as my web server. I have it up and running by adding it to my projects component. But now I want to use MG_DISABLE_HTTP_KEEP_ALIVE as it is described below in your documentation:
    https://cesanta.com/docs/overview/build-options.html#disabling-flags

but when I compile my firmware I get the following in error:
xtensa-lx106-elf-gcc.exe: error: -DESP_PLATFORM: No such file or directory

Can I get a resolution in how to fix this build error?
Am I missing any files?