Don't suggest any "devel packages" on macOS

Installing random 3rd-party "devel packages" is exactly what we don't
want people to do when building on macOS. And anyway, there is no
reason to believe this particular check will ever fail (there even is
a comment that says "MacOS X has system MIT Kerberos 5 since 10.4"),
unless something is very wrong.

Change-Id: Ic880e59358c7c510de9db29e66dfeee7f4e85b4d

configure.ac

@@ -8540,12 +8540,14 @@ if test "x$enable_postgresql_sdbc" != "xno"; then
             if test "$with_krb5" != "no"; then
                 WITH_KRB5=TRUE
                 save_LIBS=$LIBS
+                # Not sure whether it makes any sense here to search multiple potential libraries; it is not likely
+                # that the libraries where these functions are located on macOS will change, is it?
                 AC_SEARCH_LIBS(com_err, [com_err 'com_err -lssl -lcrypto' krb5 'krb5 -lcrypto -ldes -lasn1 -lroken'], [],
-                    [AC_MSG_ERROR([could not find function 'com_err' required for Kerberos 5, try installing libcom_err devel package])])
+                    [AC_MSG_ERROR([could not find function 'com_err' required for Kerberos 5])])
                 KRB5_LIBS=$LIBS
                 LIBS=$save_LIBS
                 AC_SEARCH_LIBS(krb5_sendauth, [krb5 'krb5 -lcrypto -ldes -lasn1 -lroken'], [],
-                    [AC_MSG_ERROR([could not find function 'krb5_sendauth' required for Kerberos 5, try installing krb5 devel package])])
+                    [AC_MSG_ERROR([could not find function 'krb5_sendauth' required for Kerberos 5])])
                 KRB5_LIBS="$KRB5_LIBS $LIBS"
                 LIBS=$save_LIBS
             fi