Fail during configure if unable to find ar

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.

(cherry picked from commit 2c990e6)

ticket: 7613 (new)
version_fixed: 1.9.5
status: resolved

src/aclocal.m4

@@ -1076,6 +1076,9 @@ AC_REQUIRE([AC_PROG_ARCHIVE])dnl
 AC_REQUIRE([AC_PROG_ARCHIVE_ADD])dnl
 AC_REQUIRE([AC_PROG_INSTALL])dnl
 AC_CHECK_PROG(AR, ar, ar, false)
+if test "$AR" = "false"; then
+  AC_MSG_ERROR([ar not found in PATH])
+fi
 AC_CHECK_PROG(PERL, perl, perl, false)
 if test "$ac_cv_prog_PERL" = "false"; then
   AC_MSG_ERROR(Perl is now required for Kerberos builds.)