Used external roborio compiler instead of local compiler.

Change-Id: Ifec0d68b0b51a822c906bc4f52320004ee2f5d84
diff --git a/aos/linux_code/BUILD b/aos/linux_code/BUILD
index 245acc6..de7f903 100644
--- a/aos/linux_code/BUILD
+++ b/aos/linux_code/BUILD
@@ -22,7 +22,7 @@
   deps = [
     '//aos/common:once',
     '//aos/common:die',
-    '//external:libpthread',
+    '//debian:libpthread',
   ],
 )