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 (3.11~deb9u1) update-gitignore]
---
diff --git a/.gitignore b/.gitignore
index e3c2fc2..5edd568 100644
--- a/.gitignore
+++ b/.gitignore
@@ -23,3 +23,5 @@ cmd/xb/xb
 
 # default compression test file
 enwik8*
+
+.pc
