fix building under FreeBSD 5 by enforcing disabled Kerberos 5 support

sasl/sasl.spec

@@ -101,6 +101,9 @@ AutoReqProv:  no
         saslauthd/configure
 %endif
 
+    #   enforce disabled Kerberos 5 support in saslauthd
+    echo 'ac_cv_header_krb5_h=no' >config.cache
+
     #   configure path to sasl-server config files
     %{l_shtool} subst \
         -e 's;@l_sysconfdir@;%{l_prefix}/etc/sasl/apps;g' \
@@ -124,6 +127,7 @@ AutoReqProv:  no
     LDFLAGS="$ldflags" \
     LIBS="$libs" \
     ./configure \
+        --cache-file=./config.cache \
         --prefix=%{l_prefix} \
         --sysconfdir="%{l_prefix}/etc/sasl" \
         --with-plugindir=%{l_prefix}/lib/sasl \