[committed] libstdc++: Document --enable-cstdio=stdio_pure [PR110574]

[committed] libstdc++: Document --enable-cstdio=stdio_pure [PR110574]

[Jonathan Wakely]

Pushed to trunk. Backports to 11, 12 and 13 will follow.

-- >8 --

libstdc++-v3/ChangeLog:

	PR libstdc++/110574
	* doc/xml/manual/configure.xml: Describe stdio_pure argument to
	--enable-cstdio.
	* doc/html/manual/configure.html: Regenerate.
---
 libstdc++-v3/doc/html/manual/configure.html | 11 ++++++++---
 libstdc++-v3/doc/xml/manual/configure.xml   | 11 ++++++++---
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/libstdc++-v3/doc/xml/manual/configure.xml b/libstdc++-v3/doc/xml/manual/configure.xml
index 7ff07aea886..1b8c37ce2a9 100644
--- a/libstdc++-v3/doc/xml/manual/configure.xml
+++ b/libstdc++-v3/doc/xml/manual/configure.xml
@@ -74,9 +74,14 @@
  </listitem></varlistentry>
 
  <varlistentry><term><code>--enable-cstdio=OPTION</code></term>
- <listitem><para>Select a target-specific I/O package. At the moment, the only
-	choice is to use 'stdio', a generic "C" abstraction.
-	The default is 'stdio'. This option can change the library ABI.
+ <listitem><para>Select a target-specific I/O package. The choices are 'stdio'
+       which is a generic abstraction using POSIX file I/O APIs
+       (<function>read</function>, <function>write</function>,
+       <function>lseek</function>, etc.), and 'stdio_pure' which is similar
+       but only uses standard C file I/O APIs (<function>fread</function>,
+       <function>fwrite</function>, <function>fseek</function>, etc.).
+       The 'stdio_posix' choice is a synonym for 'stdio'.
+       The default is 'stdio'. This option can change the library ABI.
      </para>
  </listitem></varlistentry>
 
-- 
2.41.0