[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/experimental/sys/unimplemented.go

@@ -0,0 +1,160 @@
+package sys
+
+import (
+	"io/fs"
+
+	"github.com/tetratelabs/wazero/sys"
+)
+
+// UnimplementedFS is an FS that returns ENOSYS for all functions,
+// This should be embedded to have forward compatible implementations.
+type UnimplementedFS struct{}
+
+// OpenFile implements FS.OpenFile
+func (UnimplementedFS) OpenFile(path string, flag Oflag, perm fs.FileMode) (File, Errno) {
+	return nil, ENOSYS
+}
+
+// Lstat implements FS.Lstat
+func (UnimplementedFS) Lstat(path string) (sys.Stat_t, Errno) {
+	return sys.Stat_t{}, ENOSYS
+}
+
+// Stat implements FS.Stat
+func (UnimplementedFS) Stat(path string) (sys.Stat_t, Errno) {
+	return sys.Stat_t{}, ENOSYS
+}
+
+// Readlink implements FS.Readlink
+func (UnimplementedFS) Readlink(path string) (string, Errno) {
+	return "", ENOSYS
+}
+
+// Mkdir implements FS.Mkdir
+func (UnimplementedFS) Mkdir(path string, perm fs.FileMode) Errno {
+	return ENOSYS
+}
+
+// Chmod implements FS.Chmod
+func (UnimplementedFS) Chmod(path string, perm fs.FileMode) Errno {
+	return ENOSYS
+}
+
+// Rename implements FS.Rename
+func (UnimplementedFS) Rename(from, to string) Errno {
+	return ENOSYS
+}
+
+// Rmdir implements FS.Rmdir
+func (UnimplementedFS) Rmdir(path string) Errno {
+	return ENOSYS
+}
+
+// Link implements FS.Link
+func (UnimplementedFS) Link(_, _ string) Errno {
+	return ENOSYS
+}
+
+// Symlink implements FS.Symlink
+func (UnimplementedFS) Symlink(_, _ string) Errno {
+	return ENOSYS
+}
+
+// Unlink implements FS.Unlink
+func (UnimplementedFS) Unlink(path string) Errno {
+	return ENOSYS
+}
+
+// Utimens implements FS.Utimens
+func (UnimplementedFS) Utimens(path string, atim, mtim int64) Errno {
+	return ENOSYS
+}
+
+// UnimplementedFile is a File that returns ENOSYS for all functions,
+// except where no-op are otherwise documented.
+//
+// This should be embedded to have forward compatible implementations.
+type UnimplementedFile struct{}
+
+// Dev implements File.Dev
+func (UnimplementedFile) Dev() (uint64, Errno) {
+	return 0, 0
+}
+
+// Ino implements File.Ino
+func (UnimplementedFile) Ino() (sys.Inode, Errno) {
+	return 0, 0
+}
+
+// IsDir implements File.IsDir
+func (UnimplementedFile) IsDir() (bool, Errno) {
+	return false, 0
+}
+
+// IsAppend implements File.IsAppend
+func (UnimplementedFile) IsAppend() bool {
+	return false
+}
+
+// SetAppend implements File.SetAppend
+func (UnimplementedFile) SetAppend(bool) Errno {
+	return ENOSYS
+}
+
+// Stat implements File.Stat
+func (UnimplementedFile) Stat() (sys.Stat_t, Errno) {
+	return sys.Stat_t{}, ENOSYS
+}
+
+// Read implements File.Read
+func (UnimplementedFile) Read([]byte) (int, Errno) {
+	return 0, ENOSYS
+}
+
+// Pread implements File.Pread
+func (UnimplementedFile) Pread([]byte, int64) (int, Errno) {
+	return 0, ENOSYS
+}
+
+// Seek implements File.Seek
+func (UnimplementedFile) Seek(int64, int) (int64, Errno) {
+	return 0, ENOSYS
+}
+
+// Readdir implements File.Readdir
+func (UnimplementedFile) Readdir(int) (dirents []Dirent, errno Errno) {
+	return nil, ENOSYS
+}
+
+// Write implements File.Write
+func (UnimplementedFile) Write([]byte) (int, Errno) {
+	return 0, ENOSYS
+}
+
+// Pwrite implements File.Pwrite
+func (UnimplementedFile) Pwrite([]byte, int64) (int, Errno) {
+	return 0, ENOSYS
+}
+
+// Truncate implements File.Truncate
+func (UnimplementedFile) Truncate(int64) Errno {
+	return ENOSYS
+}
+
+// Sync implements File.Sync
+func (UnimplementedFile) Sync() Errno {
+	return 0 // not ENOSYS
+}
+
+// Datasync implements File.Datasync
+func (UnimplementedFile) Datasync() Errno {
+	return 0 // not ENOSYS
+}
+
+// Utimens implements File.Utimens
+func (UnimplementedFile) Utimens(int64, int64) Errno {
+	return ENOSYS
+}
+
+// Close implements File.Close
+func (UnimplementedFile) Close() (errno Errno) { return }