Edit: /usr/include/X11/Xw32defs.h (1910B)
#ifndef _XW32DEFS_H
# define _XW32DEFS_H
# ifdef __GNUC__ /* mingw is more close to unix than msvc */
# if !defined(__daddr_t_defined)
typedef char *caddr_t;
# endif
# define lstat stat
# else
typedef char *caddr_t;
# define access _access
# define alloca _alloca
# define chdir _chdir
# define chmod _chmod
# define close _close
# define creat _creat
# define dup _dup
# define dup2 _dup2
# define environ _environ
# define execl _execl
# define execle _execle
# define execlp _execlp
# define execlpe _execlpe
# define execv _execv
# define execve _execve
# define execvp _execvp
# define execvpe _execvpe
# define fdopen _fdopen
# define fileno _fileno
# define fstat _fstat
# define getcwd _getcwd
# define getpid _getpid
# define hypot _hypot
# define isascii __isascii
# define isatty _isatty
# define lseek _lseek
# define mkdir _mkdir
# define mktemp _mktemp
# define open _open
# define putenv _putenv
# define read _read
# define rmdir _rmdir
# define sleep(x) Sleep((x) * 1000)
# define stat _stat
# define sys_errlist _sys_errlist
# define sys_nerr _sys_nerr
# define umask _umask
# define unlink _unlink
# define write _write
# define random rand
# define srandom srand
# define O_RDONLY _O_RDONLY
# define O_WRONLY _O_WRONLY
# define O_RDWR _O_RDWR
# define O_APPEND _O_APPEND
# define O_CREAT _O_CREAT
# define O_TRUNC _O_TRUNC
# define O_EXCL _O_EXCL
# define O_TEXT _O_TEXT
# define O_BINARY _O_BINARY
# define O_RAW _O_BINARY
# define S_IFMT _S_IFMT
# define S_IFDIR _S_IFDIR
# define S_IFCHR _S_IFCHR
# define S_IFREG _S_IFREG
# define S_IREAD _S_IREAD
# define S_IWRITE _S_IWRITE
# define S_IEXEC _S_IEXEC
# define F_OK 0
# define X_OK 1
# define W_OK 2
# define R_OK 4
# endif /* __GNUC__ */
#endif