(Eval): Increasing max-lisp-eval-depth can cause real stack overflow.

lispref/eval.texi

@@ -678,9 +678,12 @@ output of the output functions is printed in the echo area.
 @defvar max-lisp-eval-depth
 This variable defines the maximum depth allowed in calls to @code{eval},
 @code{apply}, and @code{funcall} before an error is signaled (with error
-message @code{"Lisp nesting exceeds max-lisp-eval-depth"}).  This limit,
-with the associated error when it is exceeded, is one way that Lisp
-avoids infinite recursion on an ill-defined function.
+message @code{"Lisp nesting exceeds max-lisp-eval-depth"}).
+
+This limit, with the associated error when it is exceeded, is one way
+Emacs Lisp avoids infinite recursion on an ill-defined function.  If
+you increase the value of @code{max-lisp-eval-depth} too much, such
+code can cause stack overflow instead.
 @cindex Lisp nesting error
 
 The depth limit counts internal uses of @code{eval}, @code{apply}, and