Using nRF51 SDK 10.0, it seems like many debug prints are incorrect, triggering a GCC format warning resulting in a compilation error with -Wall turned on. A workaround is turning the warnings off, but that is a bad solution.
Please fix the debug format strings so that GCC need not warn us anymore, example:
/components/ble/device_manager/device_manager_peripheral.c:582:5:
error: format '%X' expects argument of type 'unsigned int', but argument 2 has type 'uint32_t' [-Werror=format=]
DM_TRC("[DM]: Initializing Application Instance 0x%08X.\r\n", index);