Change needed to get stdbuf to successfully preload libstdbuf.so
for both 32-bit and 64-bit applications.

Since we don't link against libstdbuf.so, we need to LD_PRELOAD it.
libstdbuf.so lives in /usr/lib and /usr/lib/64, so we just use a
search path value of "" and that equates to LD_PRELOAD=libstdbuf.so,
and ld.so.1 finds the right one associated with the process class.
ie. we don't use full path names for the preload names.

This change has been passed upstream, but the GNU coreutils maintainer
turned it into a comment explaining why it's not included by default.

--- coreutils-9.5/src/stdbuf.c.orig
+++ coreutils-9.5/src/stdbuf.c
@@ -217,6 +217,7 @@
   char const *const search_path[] = {
     program_path,
     PKGLIBEXECDIR,
+    "",			/* System default */
     nullptr
   };