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 (12.9) update-gitignore]
---
diff --git a/.gitignore b/.gitignore
index 75ec23f..0dab8f7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -28,4 +28,6 @@ tmp
 internal/sandbox/test_rw
 internal/sandbox/test_ro
 test_env
-landrun
\ No newline at end of file
+landrun
+/.pc/
+/_build/
