At log_common.h we have defined:

#define LOG_LEVEL_DEBUG    (0)
#define LOG_LEVEL_INFO     (1)
#define LOG_LEVEL_WARN     (2)
#define LOG_LEVEL_ERROR    (3)
#define LOG_LEVEL_CRITICAL (4)
#define LOG_LEVEL_NONE     (5)

LOG_LEVEL.. names are very common and I have redefinition issues when another than NibBle logger is used.
Because its internal NibBle logger, proposed to use some internal names like:
BLE_LOG_LEVEL.. or NIM_BLE_LOG_LEVEL..