[experiment] add alternative wasm sqlite3 implementation available via build-tag (#2863)

This allows for building GoToSocial with [SQLite transpiled to WASM](https://github.com/ncruces/go-sqlite3) and accessed through [Wazero](https://wazero.io/).

vendor/github.com/tetratelabs/wazero/internal/sysfs/rename_windows.go

@@ -0,0 +1,55 @@
+package sysfs
+
+import (
+	"os"
+	"syscall"
+
+	"github.com/tetratelabs/wazero/experimental/sys"
+)
+
+func rename(from, to string) sys.Errno {
+	if from == to {
+		return 0
+	}
+
+	var fromIsDir, toIsDir bool
+	if fromStat, errno := stat(from); errno != 0 {
+		return errno // failed to stat from
+	} else {
+		fromIsDir = fromStat.Mode.IsDir()
+	}
+	if toStat, errno := stat(to); errno == sys.ENOENT {
+		return syscallRename(from, to) // file or dir to not-exist is ok
+	} else if errno != 0 {
+		return errno // failed to stat to
+	} else {
+		toIsDir = toStat.Mode.IsDir()
+	}
+
+	// Now, handle known cases
+	switch {
+	case !fromIsDir && toIsDir: // file to dir
+		return sys.EISDIR
+	case !fromIsDir && !toIsDir: // file to file
+		// Use os.Rename instead of syscall.Rename to overwrite a file.
+		// This uses MoveFileEx instead of MoveFile (used by syscall.Rename).
+		return sys.UnwrapOSError(os.Rename(from, to))
+	case fromIsDir && !toIsDir: // dir to file
+		return sys.ENOTDIR
+	default: // dir to dir
+
+		// We can't tell if a directory is empty or not, via stat information.
+		// Reading the directory is expensive, as it can buffer large amounts
+		// of data on fail. Instead, speculatively try to remove the directory.
+		// This is only one syscall and won't buffer anything.
+		if errno := rmdir(to); errno == 0 || errno == sys.ENOENT {
+			return syscallRename(from, to)
+		} else {
+			return errno
+		}
+	}
+}
+
+func syscallRename(from string, to string) sys.Errno {
+	return sys.UnwrapOSError(syscall.Rename(from, to))
+}