Revision r230175
> 2015-11-10 Ville Voutilainen <ville.voutilai...@gmail.com>
>
> LWG 2510, make the default constructors of library tag types
> explicit.
> * include/bits/mutex.h (defer_lock_t, try_lock_t,
> adopt_lock_t): Add an explicit default constructor.
> * include/bits/stl_pair.h (piecewise_construct_t): Likewise.
> * include/bits/uses_allocator.h (allocator_arg_t): Likewise.
> * libsupc++/new (nothrow_t): Likewise.
> * testsuite/17_intro/tag_type_explicit_ctor.cc: New.
breaks bootstrap
libtool: compile: /opt/gcc/build_w/./gcc/xgcc -shared-libgcc
-B/opt/gcc/build_w/./gcc -nostdinc++
-L/opt/gcc/build_w/x86_64-apple-darwin14.5.0/libstdc++-v3/src
-L/opt/gcc/build_w/x86_64-apple-darwin14.5.0/libstdc++-v3/src/.libs
-L/opt/gcc/build_w/x86_64-apple-darwin14.5.0/libstdc++-v3/libsupc++/.libs
-B/opt/gcc/gcc6w/x86_64-apple-darwin14.5.0/bin/
-B/opt/gcc/gcc6w/x86_64-apple-darwin14.5.0/lib/ -isystem
/opt/gcc/gcc6w/x86_64-apple-darwin14.5.0/include -isystem
/opt/gcc/gcc6w/x86_64-apple-darwin14.5.0/sys-include
-I/opt/gcc/work/libstdc++-v3/../libgcc
-I/opt/gcc/build_w/x86_64-apple-darwin14.5.0/libstdc++-v3/include/x86_64-apple-darwin14.5.0
-I/opt/gcc/build_w/x86_64-apple-darwin14.5.0/libstdc++-v3/include
-I/opt/gcc/work/libstdc++-v3/libsupc++ -D_GLIBCXX_SHARED
-fno-implicit-templates -Wall -Wextra -Wwrite-strings -Wcast-qual -Wabi
-fdiagnostics-show-location=once -fvisibility-inlines-hidden
-ffunction-sections -fdata-sections -frandom-seed=new_handler.lo -g -O2
-std=gnu++11 -c ../../../../work/libstdc++-v3/libsupc++/new_handler.cc
-fno-common -DPIC -D_GLIBCXX_SHARED -o new_handler.o
../../../../work/libstdc++-v3/libsupc++/new_handler.cc:37:39: error: converting
to 'std::nothrow_t' from initializer list would use explicit constructor
'constexpr std::nothrow_t::nothrow_t()'
const std::nothrow_t std::nothrow = { };
^
see https://gcc.gnu.org/ml/gcc-regression/2015-11/
Dominique
