AC_CHECK_FILE() does not work for cross compilation. Autoconf
documentation says:

  Be aware that, like most Autoconf macros, they test a feature of the
  host machine, and therefore, they die when cross-compiling. [1]

Test for the existance of the file directly. Of course, when cross
compiling, it's not at all clear that the host machine will run the same
distribution. And thus detecting --enable-ifcfg-rh based on the build
machine is likely wrong. Note, that we already did

    AS_IF([test -z "$hostname_persist" -a -f /etc/SuSE-release], hostname_persist=suse)

which has the same problem.

At least, build no longer fails, and the user can inspect the ./configure
summary and see which features were misdetected.

[1] https://www.gnu.org/savannah-checkouts/gnu/autoconf/manual/autoconf-2.69/html_node/Files.html