Switch to adding ./ to rpath to find CTRE code

This makes the startup scripts simpler.

Change-Id: Ida099eb1fd6a16c4f146f5e55e8c1ca1665fbbde
Signed-off-by: Austin Schuh <austin.linux@gmail.com>
diff --git a/third_party/BUILD b/third_party/BUILD
index cff81fd..8dbb529 100644
--- a/third_party/BUILD
+++ b/third_party/BUILD
@@ -24,6 +24,10 @@
 
 cc_library(
     name = "phoenix",
+    linkopts = [
+        "-Wl,-rpath",
+        "-Wl,.",
+    ],
     target_compatible_with = ["//tools/platforms/hardware:roborio"],
     visibility = ["//visibility:public"],
     deps = [