ignore libtool artifacts from cross-compile environments

Change-Id: I549ee65e72fed2d1599b3e2dfc7a37f02a8f80e6
diff --git a/.gitignore b/.gitignore
index 1ceb8d7..5a5118b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -21,6 +21,7 @@
 install-sh
 libosmo-rspro.pc
 libtool
+*-libtool
 ltmain.sh
 missing
 Makefile.in