Subject: Update .gitignore from Debian packaging branch

The Debian packaging git branch contains these updates to the upstream
.gitignore file(s).  This patch is autogenerated, to provide these
updates to users of the official Debian archive view of the package.

[dgit (11.10) update-gitignore]
---
diff --git a/.gitignore b/.gitignore
index f7e55498..2ddd1bc7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -23,3 +23,6 @@
 /trillian_map_server
 default.etcd
 cockroach-data/
+
+/.pc/
+/_build/
