add receipe for uhttpd-3p server.

bsp/buildroot_external/package/uhttpd-3p/Config.in

@@ -0,0 +1,20 @@
+menuconfig BR2_PACKAGE_UHTTPD_3P
+	bool "uhttpd (override)"
+	default n
+	help
+		uHTTPd is a tiny single threaded HTTP server with TLS, CGI and Lua
+		support. It is intended as a drop-in replacement for the Busybox
+		HTTP daemon.
+
+if BR2_PACKAGE_UHTTPD_3P
+
+config BR2_PACKAGE_UHTTPD_UBUS_SUPPORT
+	depends on BR2_PACKAGE_UHTTPD_3P
+	select BR2_PACKAGE_JSON_C
+	select BR2_PACKAGE_LIBUBUS_CPP
+	bool "UBus JSON_RPC plugin"
+	default n
+	help
+		Enables remote UBus calls over HTTP
+
+endif