Compilation with clang 6.0 fails because __USE_GNU is implicitly defined by clang #435
Description
Trying to build hazelcast-cpp-client on Ubuntu 18.04 with clang 6.0 (with libc++) I got an error:
hazelcast-cpp-client/hazelcast/src/hazelcast/util/Util.cpp:147:24: error:
cannot initialize return object of type 'int' with an rvalue of type 'char *'
return ::strerror_r(errnum, strerrbuf + numChars, buflen - numChars);
Seems like clang defines __USE_GNU, which exposes GNU implementation of strerror_r instead of a POSIX one.
You should probably change #elif defined(__llvm__) to #elif defined(__llvm__) && not defined(__USE_GNU) (or _GNU_SOURCE?). Or simply use something like that.