[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/fsapi/poll.go

@@ -0,0 +1,20 @@
+package fsapi
+
+// Pflag are bit flags used for File.Poll. Values, including zero, should not
+// be interpreted numerically. Instead, use by constants prefixed with 'POLL'.
+//
+// # Notes
+//
+//   - This is like `pollfd.events` flags for `poll` in POSIX. See
+//     https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/poll.h.html
+type Pflag uint32
+
+// Only define bitflags we support and are needed by `poll_oneoff` in wasip1
+// See https://github.com/WebAssembly/WASI/blob/snapshot-01/phases/snapshot/docs.md#eventrwflags
+const (
+	// POLLIN is a read event.
+	POLLIN Pflag = 1 << iota
+
+	// POLLOUT is a write event.
+	POLLOUT
+)