Fail during configure time if the configure script can't locate the
"ar" program, instead of producing a delayed failure during build time
by running the "false" command.  Some Solaris releases have ar in
/usr/ccs/bin, which is not in the default path for some users.

https://github.com/krb5/krb5/commit/2c990e6418cd7cee7ca178a3175b07ed6a01ffae
Commit By: tlyu
Revision: 25711
Changed Files:
U   trunk/src/aclocal.m4