CDRIVER-1044 fix -Wint-conversion on macOS
CDRIVER-1044 fix -Wint-conversion on macOS

incompatible pointer to integer conversion returning 'unsigned char *'
from a function with result type 'bool' (aka 'signed char')

Convey-Compliance/mongo-c-driver,Convey-Compliance/mongo-c-driver,Convey-Compliance/mongo-c-driver,Convey-Compliance/mongo-c-driver,Convey-Compliance/mongo-c-driver