Used external roborio compiler instead of local compiler.

Change-Id: Ifec0d68b0b51a822c906bc4f52320004ee2f5d84
diff --git a/third_party/gflags/BUILD b/third_party/gflags/BUILD
index bad36a9..532ef3f 100644
--- a/third_party/gflags/BUILD
+++ b/third_party/gflags/BUILD
@@ -42,7 +42,7 @@
     'include/gflags/gflags_completions.h',
   ],
   deps = [
-    '//external:libpthread',
+    '//debian:libpthread',
   ],
   copts = common_copts,
   includes = [ 'include' ],