Compilation error on Windows system

[misantron]

threading.c: In function 'fiftyoneDegreesSignalWait':
threading.c:145:4: warning: implicit declaration of function 'clock_gettime' [-Wimplicit-function-declaration]
    clock_gettime(CLOCK_REALTIME, &timeout);
    ^~~~~~~~~~~~~
threading.c:145:18: error: 'CLOCK_REALTIME' undeclared (first use in this function)
    clock_gettime(CLOCK_REALTIME, &timeout);
                  ^~~~~~~~~~~~~~
threading.c:145:18: note: each undeclared identifier is reported only once for each function it appears in

Unable to compile package on Windows system.
Function clock_gettime is not defined. Need Windows implementation.