[Z80] Fix missing include in c-arcmt-test

Author: Sightem

clang/tools/c-arcmt-test/c-arcmt-test.c

@@ -1,12 +1,18 @@
 /* c-arcmt-test.c */
 
+#ifndef _WIN32
+#define _POSIX_C_SOURCE 200809L
+#endif
+
 #include "clang-c/Index.h"
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
 #if defined(_WIN32)
 #include <io.h>
 #include <fcntl.h>
+#else
+#include <unistd.h>
 #endif
 
 static int print_remappings(const char *path) {