[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/poll.go

@@ -0,0 +1,18 @@
+//go:build windows || (linux && !tinygo) || darwin
+
+package sysfs
+
+import (
+	"github.com/tetratelabs/wazero/experimental/sys"
+	"github.com/tetratelabs/wazero/internal/fsapi"
+)
+
+// poll implements `Poll` as documented on sys.File via a file descriptor.
+func poll(fd uintptr, flag fsapi.Pflag, timeoutMillis int32) (ready bool, errno sys.Errno) {
+	if flag != fsapi.POLLIN {
+		return false, sys.ENOTSUP
+	}
+	fds := []pollFd{newPollFd(fd, _POLLIN, 0)}
+	count, errno := _poll(fds, timeoutMillis)
+	return count > 0, errno
+}