Disable -Werror=old-style-cast

[mnlipp]

Trying to compile (several files), I get

In file included from /home/mnl/tools/esp/esp-idf/components/freertos/esp_additions/include/freertos/idf_additions.h:20,
                 from /home/mnl/tools/esp/esp-idf/components/freertos/FreeRTOS-Kernel/include/freertos/FreeRTOS.h:1532,
                 from /home/mnl/devel/esp/WiFi-IoT-Base/externals/smooth/lib/smooth/include/smooth/core/Task.h:38,
                 from /home/mnl/devel/esp/WiFi-IoT-Base/externals/smooth/lib/smooth/include/smooth/core/network/BufferContainer.h:21,
                 from /home/mnl/devel/esp/WiFi-IoT-Base/externals/smooth/lib/smooth/include/smooth/application/network/http/IResponseOperation.h:21,
                 from /home/mnl/devel/esp/WiFi-IoT-Base/externals/smooth/lib/smooth/include/smooth/application/network/http/regular/responses/HeaderOnlyResponse.h:20,
                 from /home/mnl/devel/esp/WiFi-IoT-Base/externals/smooth/lib/smooth/include/smooth/application/network/http/regular/responses/StringResponse.h:20,
                 from /home/mnl/devel/esp/WiFi-IoT-Base/externals/smooth/lib/smooth/include/smooth/application/network/http/regular/TemplateProcessor.h:25,
                 from /home/mnl/devel/esp/WiFi-IoT-Base/externals/smooth/lib/smooth/application/network/http/regular/TemplateProcessor.cpp:18:
/home/mnl/tools/esp/esp-idf/components/freertos/FreeRTOS-Kernel/include/freertos/task.h:204:46: error: use of old-style cast to 'BaseType_t' {aka 'int'} [-Werror=old-style-cast]
  204 | #define tskNO_AFFINITY      ( ( BaseType_t ) 0x7FFFFFFF )
      |                                              ^~~~~~~~~~
/home/mnl/devel/esp/WiFi-IoT-Base/externals/smooth/lib/smooth/include/smooth/core/Task.h:95:29: note: in expansion of macro 'tskNO_AFFINITY'
   95 |                  int core = tskNO_AFFINITY);
      |                             ^~~~~~~~~~~~~~

I cannot change how FreeRTOS does it's casting, but even if I would (I actually tried) and replaced the old style casts with new style casts in the header files, compiling with gcc fails, of course.

It seems to me that the only solution is to get rid of this -Werror=old-style-cast.

Aside from this being an issue, can somebody tell me how to do this without spending a week on understanding this extremely complicated build system? Currently, this prevents me from using smooth (which I'd really like to do).