ignore gdb/debugging files

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

.gitignore

@@ -18,6 +18,13 @@ lib
 .*.dep
 /*.log
 
+#
+# Debugging files
+#
+.gdb_history
+.gdbinit
+core
+
 #
 # Backups / patches
 #