Use compile_et from e2fsprogs rather than building the native and useless one
from heimdal.

Idea from:
http://comments.gmane.org/gmane.comp.encryption.kerberos.heimdal.general/6572

Status: Backport from upstream git.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>

diff -Nura heimdal-1.5.3.orig/cf/check-compile-et.m4 heimdal-1.5.3.et/cf/check-compile-et.m4
--- heimdal-1.5.3.orig/cf/check-compile-et.m4	2012-12-09 19:06:44.000000000 -0300
+++ heimdal-1.5.3.et/cf/check-compile-et.m4	2013-12-18 14:20:04.025925879 -0300
@@ -3,12 +3,12 @@
 dnl CHECK_COMPILE_ET
 AC_DEFUN([CHECK_COMPILE_ET], [
 
-AC_CHECK_PROG(COMPILE_ET, compile_et, [compile_et])
+AC_CHECK_PROG(COMPILE_ET, compile_et, [compile_et], [no])
 
 krb_cv_compile_et="no"
 krb_cv_com_err_need_r=""
 krb_cv_compile_et_cross=no
-if test "${COMPILE_ET}" = "compile_et"; then
+if test "$COMPILE_ET" != "no"; then
 
 dnl We have compile_et.  Now let's see if it supports `prefix' and `index'.
 AC_MSG_CHECKING(whether compile_et has the features we need)