+#ifndef HAVE_ERRNO_DECL
+extern int errno;
+#endif
+
+#define SUPPORT_LINKS HAVE_READLINK
+#define SUPPORT_HARD_LINKS HAVE_LINK
+
+#ifndef HAVE_LCHOWN
+#define lchown chown
+#endif
+
+#define SIGNAL_CAST (RETSIGTYPE (*)())
+
+#ifndef EWOULDBLOCK
+#define EWOULDBLOCK EAGAIN
+#endif
+
+#ifndef STDIN_FILENO
+#define STDIN_FILENO 0
+#endif
+
+#ifndef STDOUT_FILENO
+#define STDOUT_FILENO 1
+#endif
+
+#ifndef STDERR_FILENO
+#define STDERR_FILENO 2
+#endif
+
+#ifndef S_IWUSR
+#define S_IWUSR 0200
+#endif
+
+#ifndef _S_IFMT
+#define _S_IFMT 0170000
+#endif
+
+#ifndef _S_IFLNK
+#define _S_IFLNK 0120000
+#endif
+
+#ifndef S_ISLNK
+#define S_ISLNK(mode) (((mode) & (_S_IFMT)) == (_S_IFLNK))
+#endif
+
+#ifndef S_ISBLK
+#define S_ISBLK(mode) (((mode) & (_S_IFMT)) == (_S_IFBLK))
+#endif
+
+#ifndef S_ISCHR
+#define S_ISCHR(mode) (((mode) & (_S_IFMT)) == (_S_IFCHR))
+#endif
+
+#ifndef S_ISSOCK
+#ifdef _S_IFSOCK
+#define S_ISSOCK(mode) (((mode) & (_S_IFMT)) == (_S_IFSOCK))