.gitignore: ignore src/**/.dirstamp

.dirstamp files are a build artifact created when GNU autoconf
projects have files spread over multiple directories.

Author: jasonish

.gitignore

@@ -59,6 +59,7 @@ src/*.orig
 src/*.plist/*
 src/TAGS
 src/suricata
+src/**/*.dirstamp
 stamp-h1
 src/build-info.h
 test.sh