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

diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index d85eadb..721edd1 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -250,8 +250,9 @@
    Print low-level information to stderr about the state of CPython's memory
    allocator.
 
-   If Python is :option:`configured --with-pydebug <--with-pydebug>`, it also
-   performs some expensive internal consistency checks.
+   If Python is `built in debug mode <debug-build>` (:option:`configure
+   --with-pydebug option <--with-pydebug>`), it also performs some expensive
+   internal consistency checks.
 
    .. versionadded:: 3.3