Add a "fork" of musl as //fusl.

fusl/src/errno/__strerror.h

+/* This file is sorted such that 'errors' which represent exceptional
+ * conditions under which a correct program may fail come first, followed
+ * by messages that indicate an incorrect program or system failure. The
+ * macro E() along with double-inclusion is used to ensure that ordering
+ * of the strings remains synchronized. */
+
+E(EILSEQ,       "Illegal byte sequence")
+E(EDOM,         "Domain error")
+E(ERANGE,       "Result not representable")
+
+E(ENOTTY,       "Not a tty")
+E(EACCES,       "Permission denied")
+E(EPERM,        "Operation not permitted")
+E(ENOENT,       "No such file or directory")
+E(ESRCH,        "No such process")
+E(EEXIST,       "File exists")
+
+E(EOVERFLOW,    "Value too large for data type")
+E(ENOSPC,       "No space left on device")
+E(ENOMEM,       "Out of memory")
+
+E(EBUSY,        "Resource busy")
+E(EINTR,        "Interrupted system call")
+E(EAGAIN,       "Resource temporarily unavailable")
+E(ESPIPE,       "Invalid seek")
+
+E(EXDEV,        "Cross-device link")
+E(EROFS,        "Read-only file system")
+E(ENOTEMPTY,    "Directory not empty")
+
+E(ECONNRESET,   "Connection reset by peer")
+E(ETIMEDOUT,    "Operation timed out")
+E(ECONNREFUSED, "Connection refused")
+E(EHOSTDOWN,    "Host is down")
+E(EHOSTUNREACH, "Host is unreachable")
+E(EADDRINUSE,   "Address in use")
+
+E(EPIPE,        "Broken pipe")
+E(EIO,          "I/O error")
+E(ENXIO,        "No such device or address")
+E(ENOTBLK,      "Block device required")
+E(ENODEV,       "No such device")
+E(ENOTDIR,      "Not a directory")
+E(EISDIR,       "Is a directory")
+E(ETXTBSY,      "Text file busy")
+E(ENOEXEC,      "Exec format error")
+
+E(EINVAL,       "Invalid argument")
+
+E(E2BIG,        "Argument list too long")
+E(ELOOP,        "Symbolic link loop")
+E(ENAMETOOLONG, "Filename too long")
+E(ENFILE,       "Too many open files in system")
+E(EMFILE,       "No file descriptors available")
+E(EBADF,        "Bad file descriptor")
+E(ECHILD,       "No child process")
+E(EFAULT,       "Bad address")
+E(EFBIG,        "File too large")
+E(EMLINK,       "Too many links")
+E(ENOLCK,       "No locks available")
+
+E(EDEADLK,      "Resource deadlock would occur")
+E(ENOTRECOVERABLE, "State not recoverable")
+E(EOWNERDEAD,   "Previous owner died")
+E(ECANCELED,    "Operation canceled")
+E(ENOSYS,       "Function not implemented")
+E(ENOMSG,       "No message of desired type")
+E(EIDRM,        "Identifier removed")
+E(ENOSTR,       "Device not a stream")
+E(ENODATA,      "No data available")
+E(ETIME,        "Device timeout")
+E(ENOSR,        "Out of streams resources")
+E(ENOLINK,      "Link has been severed")
+E(EPROTO,       "Protocol error")
+E(EBADMSG,      "Bad message")
+E(EBADFD,       "File descriptor in bad state")
+E(ENOTSOCK,     "Not a socket")
+E(EDESTADDRREQ, "Destination address required")
+E(EMSGSIZE,     "Message too large")
+E(EPROTOTYPE,   "Protocol wrong type for socket")
+E(ENOPROTOOPT,  "Protocol not available")
+E(EPROTONOSUPPORT,"Protocol not supported")
+E(ESOCKTNOSUPPORT,"Socket type not supported")
+E(ENOTSUP,      "Not supported")
+E(EPFNOSUPPORT, "Protocol family not supported")
+E(EAFNOSUPPORT, "Address family not supported by protocol")
+E(EADDRNOTAVAIL,"Address not available")
+E(ENETDOWN,     "Network is down")
+E(ENETUNREACH,  "Network unreachable")
+E(ENETRESET,    "Connection reset by network")
+E(ECONNABORTED, "Connection aborted")
+E(ENOBUFS,      "No buffer space available")
+E(EISCONN,      "Socket is connected")
+E(ENOTCONN,     "Socket not connected")
+E(ESHUTDOWN,    "Cannot send after socket shutdown")
+E(EALREADY,     "Operation already in progress")
+E(EINPROGRESS,  "Operation in progress")
+E(ESTALE,       "Stale file handle")
+E(EREMOTEIO,    "Remote I/O error")
+E(EDQUOT,       "Quota exceeded")
+E(ENOMEDIUM,    "No medium found")
+E(EMEDIUMTYPE,  "Wrong medium type")
+
+E(0,            "No error information")