Imported Upstream version 5.12.0.220

Former-commit-id: c477e03582759447177c6d4bf412cd2355aad476

support/unistd.c

@@ -20,6 +20,16 @@
 #include <errno.h>
 #include <limits.h>
 #include <string.h>     /* for swab(3) on Mac OS X */
+#if defined(_AIX)
+#include <netdb.h> /* for get/setdomainname */
+/*
+ * Yet more stuff in libc that isn't in headers.
+ * Python does the same thing we do here.
+ * see: bugs.python.org/issue18259
+ */
+extern int sethostname(const char *, size_t);
+extern int sethostid(long);
+#endif
 
 #include "mph.h" /* Don't remove or move after map.h! Works around issues with Android SDK unified headers */
 #include "map.h"