Eh my bad, in Arduino-ESP32, the sdkconfig.h is included, since it builds on ESP-IDF.
I reread your log and you are compiling for an ESP8266 (esp_wroom_02). A chip that has no native bluetooth capability, only WiFi. And the NimBLE (GitHub - h2zero/NimBLE-Arduino: A fork of the NimBLE library structured for compilation with Ardruino, for use with ESP32, nRF5x.) is consequently for an ESP32.
There is something really fundamentally wrong here. Are you sure the target microcontroller is an ESP8266? How could compilation of this ESP32 bluetooth library ever work before?