[committed] libstdc++: Include C++17 features in doxygen API docs

[Jonathan Wakely via Gcc-patches]

libstdc++-v3/ChangeLog:

        * doc/doxygen/user.cfg.in (PREDEFINED): Use __cplusplus=201703L
        so that C++17 features are documented.

Tested x86_64-linux. Committed to trunk.


commit 925eb6a0fbf5aa6e99e8b461a41cbeeab507afcd
Author: Jonathan Wakely <jwak...@redhat.com>
Date:   Mon Oct 12 18:14:01 2020

    libstdc++: Include C++17 features in doxygen API docs
    
    libstdc++-v3/ChangeLog:
    
            * doc/doxygen/user.cfg.in (PREDEFINED): Use __cplusplus=201703L
            so that C++17 features are documented.

diff --git a/libstdc++-v3/doc/doxygen/user.cfg.in 
b/libstdc++-v3/doc/doxygen/user.cfg.in
index 19f8ffd8230..4495b1c9ede 100644
--- a/libstdc++-v3/doc/doxygen/user.cfg.in
+++ b/libstdc++-v3/doc/doxygen/user.cfg.in
@@ -2250,7 +2250,7 @@ INCLUDE_FILE_PATTERNS  =
 # recursively expanded use the := operator instead of the = operator.
 # This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
 
-PREDEFINED             = __cplusplus=201402L \
+PREDEFINED             = __cplusplus=201703L \
                          __GTHREADS \
                          _GLIBCXX_HAS_GTHREADS \
                          _GLIBCXX_HAVE_TLS \