This problem is very simple. All the header files from the FreeRTOS are correctly escaped from cplusplus compilations, except the "FreeRTOS-Plus-CLI/FreeRTOS_CLI.h"
It’s missing on the start:
#ifdef __cplusplus
extern "C" {
#endif
and on the end:
#ifdef __cplusplus
}
#endif
This can mean a time wasted looking for the problem on a compilation.