Don't rely on debian's way to multilib/multiarch.

https://bugs.gentoo.org/550344
--- a/eatmydata.in
+++ b/eatmydata.in
@@ -17,5 +17,4 @@
 
-export `dpkg-architecture|grep DEB_BUILD_MULTIARCH`
+shlib="@libexecdir@/eatmydata.sh"
 
-shlib="/usr/lib/$DEB_BUILD_MULTIARCH/eatmydata.sh"
 if [ -f "$shlib" ]; then