switch to go vendoring

vendor/github.com/mattn/go-sqlite3/sqlite3_opt_icu.go

@@ -0,0 +1,17 @@
+// 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 sqlite_icu icu
+
+package sqlite3
+
+/*
+#cgo LDFLAGS: -licuuc -licui18n
+#cgo CFLAGS: -DSQLITE_ENABLE_ICU
+#cgo darwin CFLAGS: -I/usr/local/opt/icu4c/include
+#cgo darwin LDFLAGS: -L/usr/local/opt/icu4c/lib
+#cgo openbsd LDFLAGS: -lsqlite3
+*/
+import "C"