bpo-43774: Add more links to configure options (GH-25363)

diff --git a/Doc/using/unix.rst b/Doc/using/unix.rst
index b5b26ec..09dd5b0 100644
--- a/Doc/using/unix.rst
+++ b/Doc/using/unix.rst
@@ -168,6 +168,7 @@
          $ popd
 
 3. Build Python with custom OpenSSL
+   (see the configure `--with-openssl` and `--with-openssl-rpath` options)
 
    .. code-block:: shell-session