howto.html: Document change from _GLIBCPP_CONCEPT_CHECKS to _GLIBCXX_CONCEPT_CHECKS in 3.4.

2004-11-16  Jonathan Wakely  <redi@gcc.gnu.org>

	* docs/html/19_diagnostics/howto.html: Document change from
	_GLIBCPP_CONCEPT_CHECKS to _GLIBCXX_CONCEPT_CHECKS in 3.4.

From-SVN: r90729

libstdc++-v3/ChangeLog

+2004-11-16  Jonathan Wakely  <redi@gcc.gnu.org>
+
+	* docs/html/19_diagnostics/howto.html: Document change from
+	_GLIBCPP_CONCEPT_CHECKS to _GLIBCXX_CONCEPT_CHECKS in 3.4.
+
 2004-11-16  Matthias Klose  <doko@debian.org>
 
 	* docs/doxygen/user.cfg.in: Set HAVE_DOT to NO.

libstdc++-v3/docs/html/19_diagnostics/howto.html

@@ -110,11 +110,14 @@
       object file.  The checks are also cleaner and easier to read and
       understand.
    </p>
-   <p>For GCC 3.0 and 3.1 they are off by default.  They can be enabled at
-      configure time with
+   <p>They are off by default for all versions of GCC from 3.0 to 3.4 (the
+      latest release at the time of writing).
+      They can be enabled at configure time with
       <a href="../configopts.html"><code>--enable-concept-checks</code></a>.
-      For 3.1 you can instead #define _GLIBCPP_CONCEPT_CHECKS to enable them
-      on a per-translation-unit basis.
+      You can enable them on a per-translation-unit basis with
+      <code>#define _GLIBCXX_CONCEPT_CHECKS</code> for GCC 3.4 and higher
+      (or with <code>#define _GLIBCPP_CONCEPT_CHECKS</code> for versions
+      3.1, 3.2 and 3.3).
    </p>
    <p>Return <a href="#top">to top of page</a> or
       <a href="../faq/index.html">to the FAQ</a>.