add vendoring

vendor/github.com/mattn/go-sqlite3/sqlite3_windows.go

@@ -0,0 +1,18 @@
+// Copyright (C) 2019 Yasuhiro Matsumoto <mattn.jp@gmail.com>.
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+
+// +build windows
+
+package sqlite3
+
+/*
+#cgo CFLAGS: -I.
+#cgo CFLAGS: -fno-stack-check
+#cgo CFLAGS: -fno-stack-protector
+#cgo CFLAGS: -mno-stack-arg-probe
+#cgo LDFLAGS: -lmingwex -lmingw32
+#cgo windows,386 CFLAGS: -D_USE_32BIT_TIME_T
+*/
+import "C"