gh-108765: multiprocessing.h includes <unistd.h>

Author: vstinner

Modules/_multiprocessing/multiprocessing.h

@@ -10,6 +10,8 @@
 #include "pythread.h"
 #include "pycore_signal.h"        // _PyOS_IsMainThread()
 
+#include <unistd.h>               // sysconf()
+
 /*
  * Platform includes and definitions
  */