Ignore quilt .pc directory, used in deb packaging

Debian packaging uses quilt to manage patches. Book-keeping for them is
done using quilt (either directly, or in a compatible format), and
tracked in the directory .pc .

Signed-off-by: Tzafrir Cohen <tzafrir.cohen@xorcom.com>

.gitignore

@@ -1,6 +1,8 @@
 # Files that are generated as part of the build process which we do not want git
 # to track.
 
+/.pc
+
 *.[oa]
 *.mod
 *.mod.[oc]