gitignore: only ignore build system files in the top directory
diff --git a/.gitignore b/.gitignore
index c3dfe0a..1a15de1 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,16 +5,18 @@
 .libs/
 Makefile
 Makefile.in
-aclocal.m4
-autom4te.cache/
-build-aux/
-config.h
-config.h.in
-config.log
-config.status
-configure
-libtool
-stamp-h1
+
+/aclocal.m4
+/autom4te.cache/
+/build-aux/
+/config.h
+/config.h.in
+/config.log
+/config.status
+/configure
+/libtool
+/stamp-h1
+
 *~
 .*.swp
 cscope.out