.gitignore: Add configure~

Change-Id: Ie46723fe3ad5b27813c102e068f433215692271f
diff --git a/.gitignore b/.gitignore
index 2852b4d..c7ac391 100644
--- a/.gitignore
+++ b/.gitignore
@@ -8,6 +8,7 @@
 aclocal.m4
 config.*
 configure
+configure~
 compile
 depcomp
 libtool