libstdc++: Make certain exceptions transaction_safe.

libitm/ChangeLog

libitm/testsuite/libitm.c++/libstdc++-safeexc.C

libstdc++-v3/ChangeLog

libstdc++-v3/acinclude.m4

libstdc++-v3/config.h.in

libstdc++-v3/config/abi/pre/gnu.ver

libstdc++-v3/configure

libstdc++-v3/configure.ac

libstdc++-v3/include/Makefile.am

libstdc++-v3/include/Makefile.in

libstdc++-v3/include/bits/basic_string.h

libstdc++-v3/include/bits/c++config

libstdc++-v3/include/std/stdexcept

libstdc++-v3/libsupc++/eh_exception.cc

libstdc++-v3/libsupc++/exception

libstdc++-v3/src/c++11/cow-stdexcept.cc

libstdc++-v3/testsuite/util/testsuite_abi.cc