Macro _POSIX_C_SOURCE breaks compilation on macOS

[disigma]

The definition of macro _POSIX_C_SOURCE makes some types in macOS undefined.

libmaxminddb/include/maxminddb.h

Line 17 in d918412

#define _POSIX_C_SOURCE 200809L

I got the following compilation error messages:

/xxxx/usr/include/sys/ucred.h:101:2: error: unknown type name 'u_int'
        u_int   cr_version;             /* structure layout version */
        ^

See the https://stackoverflow.com/questions/15393905/c-pcap-library-unknown-types-error , the error is caused by definition of macro _POSIX_SOURCE.

Is it necessary to define this macro? Can it be removed?

[horgh]

Yeah, we want it.

Adding this to your code may work (I'm not sure):

#include <sys/types.h>