camlistored: make sqlite a build option.

Change-Id: Ib3624f162aae2130e524cf6a04c3f0fa8f07a01c

server/camlistored/option_sqlite.go

@@ -0,0 +1,16 @@
+// +build with_sqlite
+
+// If the "with_sqlite" build tag is specified, the sqlite index driver
+// is also built & loaded:
+//
+//    go install -tags=with_sqlite camlistore.org/server/camlistored
+//
+// This is an option because the sqlite3 SQL driver requires cgo & the
+// SQLite3 C library available. We want it to still be possible to
+// have a pure Go server too.
+
+package main
+
+import (
+	_ "camlistore.org/pkg/index/sqlite"
+)