[gcc/devel/c++-coroutines] Merge master r10-7570.

[Iain D Sandoe]

https://gcc.gnu.org/g:395587a4752dafc9ce066cf9b0156ba357719e14

commit 395587a4752dafc9ce066cf9b0156ba357719e14
Merge: 07f38c63650 e83714f65d1
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Mon Apr 6 20:39:26 2020 +0100

    Merge master r10-7570.
    
    2020-04-06  Iain Sandoe  <iain@sandoe.co.uk>
    
            * Merge master r10-7570-ge83714f65d.

Diff:

 gcc/ChangeLog                                      |  27 ++++++
 gcc/DATESTAMP                                      |   2 +-
 gcc/config/microblaze/microblaze.c                 |   2 +-
 gcc/config/microblaze/microblaze.md                |   2 +-
 gcc/cp/ChangeLog                                   |  11 +++
 gcc/cp/init.c                                      |   2 +
 gcc/cp/mangle.c                                    |   1 +
 gcc/doc/extend.texi                                |   2 +-
 gcc/dwarf2out.c                                    |  15 ++-
 gcc/lra-lives.c                                    |   6 ++
 gcc/testsuite/ChangeLog                            |  22 +++++
 gcc/testsuite/g++.dg/abi/mangle75.C                |  13 +++
 ...late-traits.C => co-await-16-template-traits.C} |   0
 ...e-comp-ref.C => co-await-17-capture-comp-ref.C} |   0
 gcc/testsuite/g++.dg/cpp2a/paren-init22.C          |  15 +++
 gcc/testsuite/g++.dg/debug/pr94459.C               |  58 ++++++++++++
 .../gcc.target/microblaze/others/builtin-trap.c    |   2 +-
 libgcc/ChangeLog                                   |   4 +
 libgcc/generic-morestack.c                         |   2 +-
 libstdc++-v3/ChangeLog                             |  25 +++++
 .../doc/html/manual/appendix_contributing.html     |   2 +-
 .../doc/xml/manual/appendix_contributing.xml       |   2 +-
 libstdc++-v3/include/bits/char_traits.h            | 101 +++++++++++++++++----
 libstdc++-v3/include/std/string_view               |   1 +
 .../operations/copy/char/constexpr.cc              |  32 +++++++
 .../operations/copy/wchar_t/constexpr.cc           |  32 +++++++
 26 files changed, 353 insertions(+), 28 deletions(-)