diff --git a/src/syscall/syscall_libc.go b/src/syscall/syscall_libc.go
index 5c701710..313ae36f 100644
--- a/src/syscall/syscall_libc.go
+++ b/src/syscall/syscall_libc.go
@@ -146,6 +146,8 @@ func Unlink(path string) (err error) {
 	return
 }
 
+func Faccessat(dirfd int, path string, mode uint32, flags int) (err error)
+
 func Kill(pid int, sig Signal) (err error) {
 	return ENOSYS // TODO
 }
@@ -290,6 +292,18 @@ func Environ() []string {
 	return envs
 }
 
+// BytePtrFromString returns a pointer to a NUL-terminated array of
+// bytes containing the text of s. If s contains a NUL byte at any
+// location, it returns (nil, EINVAL).
+func BytePtrFromString(s string) (*byte, error) {
+	for i := 0; i < len(s); i++ {
+		if s[i] == 0 {
+			return nil, EINVAL
+		}
+	}
+	return &cstring(s)[0], nil
+}
+
 // cstring converts a Go string to a C string.
 func cstring(s string) []byte {
 	data := make([]byte, len(s)+1)
diff --git a/src/syscall/syscall_libc_darwin.go b/src/syscall/syscall_libc_darwin.go
index 2628185d..2a0dd206 100644
--- a/src/syscall/syscall_libc_darwin.go
+++ b/src/syscall/syscall_libc_darwin.go
@@ -52,6 +52,9 @@ const (
 	DT_SOCK    = 0xc
 	DT_UNKNOWN = 0x0
 	DT_WHT     = 0xe
+	F_GETFL    = 0x3
+	F_SETFL    = 0x4
+	O_NONBLOCK = 0x4
 )
 
 // Source: https://opensource.apple.com/source/xnu/xnu-7195.81.3/bsd/sys/errno.h.auto.html
@@ -62,6 +65,7 @@ const (
 	EEXIST      Errno = 17
 	EINTR       Errno = 4
 	ENOTDIR     Errno = 20
+	EISDIR      Errno = 21
 	EINVAL      Errno = 22
 	EMFILE      Errno = 24
 	EPIPE       Errno = 32
@@ -271,6 +275,32 @@ func Getpagesize() int {
 	return int(libc_getpagesize())
 }
 
+// The following RawSockAddr* types have been copied from the Go source tree and
+// are here purely to fix build errors.
+
+type RawSockaddr struct {
+	Len    uint8
+	Family uint8
+	Data   [14]int8
+}
+
+type RawSockaddrInet4 struct {
+	Len    uint8
+	Family uint8
+	Port   uint16
+	Addr   [4]byte /* in_addr */
+	Zero   [8]int8
+}
+
+type RawSockaddrInet6 struct {
+	Len      uint8
+	Family   uint8
+	Port     uint16
+	Flowinfo uint32
+	Addr     [16]byte /* in6_addr */
+	Scope_id uint32
+}
+
 // int pipe(int32 *fds);
 //
 //export pipe
diff --git a/src/syscall/syscall_libc_nintendoswitch.go b/src/syscall/syscall_libc_nintendoswitch.go
index 698a7e43..707650d3 100644
--- a/src/syscall/syscall_libc_nintendoswitch.go
+++ b/src/syscall/syscall_libc_nintendoswitch.go
@@ -71,6 +71,14 @@ func Getpagesize() int {
 	return 4096 // TODO
 }
 
+type RawSockaddrInet4 struct {
+	// stub
+}
+
+type RawSockaddrInet6 struct {
+	// stub
+}
+
 // int open(const char *pathname, int flags, mode_t mode);
 //
 //export open
diff --git a/src/syscall/syscall_libc_wasi.go b/src/syscall/syscall_libc_wasi.go
index 12959238..18118ab4 100644
--- a/src/syscall/syscall_libc_wasi.go
+++ b/src/syscall/syscall_libc_wasi.go
@@ -87,6 +87,22 @@ const (
 	PROT_READ  = 1
 	PROT_WRITE = 2
 	PROT_EXEC  = 4
+
+	// ../../lib/wasi-libc/expected/wasm32-wasi/predefined-macros.txt
+	F_GETFL = 3
+	F_SETFL = 4
+)
+
+// These values are needed as a stub until Go supports WASI as a full target.
+// The constant values don't have a meaning and don't correspond to anything
+// real.
+const (
+	_ = iota
+	SYS_FCNTL
+	SYS_FCNTL64
+	SYS_FSTATAT64
+	SYS_OPENAT
+	SYS_UNLINKAT
 )
 
 //go:extern errno
@@ -308,6 +324,32 @@ func Getpagesize() int {
 	return 65536
 }
 
+type Utsname struct {
+	Sysname    [65]int8
+	Nodename   [65]int8
+	Release    [65]int8
+	Version    [65]int8
+	Machine    [65]int8
+	Domainname [65]int8
+}
+
+// Stub Utsname, needed because WASI pretends to be linux/arm.
+func Uname(buf *Utsname) (err error)
+
+type RawSockaddrInet4 struct {
+	// stub
+}
+
+type RawSockaddrInet6 struct {
+	// stub
+}
+
+// This is a stub, it is not functional.
+func Syscall(trap, a1, a2, a3 uintptr) (r1, r2 uintptr, err Errno)
+
+// This is a stub, it is not functional.
+func Syscall6(trap, a1, a2, a3, a4, a5, a6 uintptr) (r1, r2 uintptr, err Errno)
+
 // int stat(const char *path, struct stat * buf);
 //
 //export stat
diff --git a/src/syscall/syscall_nonhosted.go b/src/syscall/syscall_nonhosted.go
index 04a77680..87d4d9d7 100644
--- a/src/syscall/syscall_nonhosted.go
+++ b/src/syscall/syscall_nonhosted.go
@@ -210,3 +210,11 @@ func Getpagesize() int {
 	// common assumption when pagesize is unknown
 	return 4096
 }
+
+type RawSockaddrInet4 struct {
+	// stub
+}
+
+type RawSockaddrInet6 struct {
+	// stub
+}
diff --git a/src/syscall/syscall_unix.go b/src/syscall/syscall_unix.go
index 0cd8f286..23d81fb8 100644
--- a/src/syscall/syscall_unix.go
+++ b/src/syscall/syscall_unix.go
@@ -1,3 +1,18 @@
 package syscall
 
 func Exec(argv0 string, argv []string, envv []string) (err error)
+
+// The two SockaddrInet* structs have been copied from the Go source tree.
+
+type SockaddrInet4 struct {
+	Port int
+	Addr [4]byte
+	raw  RawSockaddrInet4
+}
+
+type SockaddrInet6 struct {
+	Port   int
+	ZoneId uint32
+	Addr   [16]byte
+	raw    RawSockaddrInet6
+}