syscall: use wasi-libc tables for wasm/js target

Instead of using fake tables for errno and others, use the ones that
correspond to wasi-libc.

src/syscall/env_libc.go

@@ -1,4 +1,4 @@
-//go:build nintendoswitch || wasip1
+//go:build js || nintendoswitch || wasip1
 
 package syscall
 

src/syscall/errno_other.go

@@ -1,4 +1,4 @@
-//go:build !wasip1 && !wasip2
+//go:build !js && !wasip1 && !wasip2
 
 package syscall
 

src/syscall/errno_wasip1.go → src/syscall/errno_wasilibc.go

@@ -1,4 +1,4 @@
-//go:build wasip1
+//go:build wasip1 || js
 
 package syscall
 

src/syscall/syscall_libc.go

@@ -1,4 +1,4 @@
-//go:build nintendoswitch || wasip1 || wasip2
+//go:build js || nintendoswitch || wasip1 || wasip2
 
 package syscall
 

src/syscall/syscall_libc_wasi.go

@@ -1,4 +1,6 @@
-//go:build wasip1 || wasip2
+//go:build js || wasip1 || wasip2
+
+// Note: also including js in here because it also uses wasi-libc.
 
 package syscall
 

src/syscall/syscall_nonhosted.go

@@ -1,4 +1,4 @@
-//go:build baremetal || js || wasm_unknown
+//go:build baremetal || wasm_unknown
 
 package syscall
 

src/syscall/tables_nonhosted.go

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build baremetal || nintendoswitch || js || wasm_unknown
+//go:build baremetal || nintendoswitch || wasm_unknown
 
 package syscall