[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/dir.go

@@ -0,0 +1,92 @@
+package sys
+
+import (
+	"fmt"
+	"io/fs"
+
+	"github.com/tetratelabs/wazero/sys"
+)
+
+// FileType is fs.FileMode masked on fs.ModeType. For example, zero is a
+// regular file, fs.ModeDir is a directory and fs.ModeIrregular is unknown.
+//
+// Note: This is defined by Linux, not POSIX.
+type FileType = fs.FileMode
+
+// Dirent is an entry read from a directory via File.Readdir.
+//
+// # Notes
+//
+//   - This extends `dirent` defined in POSIX with some fields defined by
+//     Linux. See https://man7.org/linux/man-pages/man3/readdir.3.html and
+//     https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/dirent.h.html
+//   - This has a subset of fields defined in sys.Stat_t. Notably, there is no
+//     field corresponding to Stat_t.Dev because that value will be constant
+//     for all files in a directory. To get the Dev value, call File.Stat on
+//     the directory File.Readdir was called on.
+type Dirent struct {
+	// Ino is the file serial number, or zero if not available. See Ino for
+	// more details including impact returning a zero value.
+	Ino sys.Inode
+
+	// Name is the base name of the directory entry. Empty is invalid.
+	Name string
+
+	// Type is fs.FileMode masked on fs.ModeType. For example, zero is a
+	// regular file, fs.ModeDir is a directory and fs.ModeIrregular is unknown.
+	//
+	// Note: This is defined by Linux, not POSIX.
+	Type fs.FileMode
+}
+
+func (d *Dirent) String() string {
+	return fmt.Sprintf("name=%s, type=%v, ino=%d", d.Name, d.Type, d.Ino)
+}
+
+// IsDir returns true if the Type is fs.ModeDir.
+func (d *Dirent) IsDir() bool {
+	return d.Type == fs.ModeDir
+}
+
+// DirFile is embeddable to reduce the amount of functions to implement a file.
+type DirFile struct{}
+
+// IsAppend implements File.IsAppend
+func (DirFile) IsAppend() bool {
+	return false
+}
+
+// SetAppend implements File.SetAppend
+func (DirFile) SetAppend(bool) Errno {
+	return EISDIR
+}
+
+// IsDir implements File.IsDir
+func (DirFile) IsDir() (bool, Errno) {
+	return true, 0
+}
+
+// Read implements File.Read
+func (DirFile) Read([]byte) (int, Errno) {
+	return 0, EISDIR
+}
+
+// Pread implements File.Pread
+func (DirFile) Pread([]byte, int64) (int, Errno) {
+	return 0, EISDIR
+}
+
+// Write implements File.Write
+func (DirFile) Write([]byte) (int, Errno) {
+	return 0, EISDIR
+}
+
+// Pwrite implements File.Pwrite
+func (DirFile) Pwrite([]byte, int64) (int, Errno) {
+	return 0, EISDIR
+}
+
+// Truncate implements File.Truncate
+func (DirFile) Truncate(int64) Errno {
+	return EISDIR
+}