Use POSIXErrorCode instead of direct errno E constants from libc

wasi-libc's E constants cannot be imported directly by ClangImporter,
so we should use `POSIXErrorCode` from Swift instead.

Author: kateinoigakukun

Sources/FoundationEssentials/Error/CocoaError+FilePath.swift

@@ -94,7 +94,7 @@ extension CocoaError {
         var userInfo = userInfo
 
         // (130280235) POSIXError.Code does not have a case for EOPNOTSUPP
-        if errno != EOPNOTSUPP {
+        if errno != POSIXErrorCode.EOPNOTSUPP.rawValue {
             guard let code = POSIXError.Code(rawValue: errno) else {
                 fatalError("Invalid posix errno \(errno)")
             }