C++11 forbids a compound statement, as seen in the definition
of __glibcxx_assert(), in a constexpr function. This patch
open-codes the assertion in `bitset<>::operator[] const` for
C++11 to fix a failure in `g++.old-deja/g++.martin/bitset1.C`.
Also, it adds `{ dg-do compile }` in another test to suppress
a spurious UNRESOLVED complaint.
libstdc++-v3/ChangeLog:
* include/std/bitset (operator[]() const): Customize bounds
check for C++11 case.
* testsuite/20_util/bitset/access/subscript_const_neg.cc:
Suppress UNRESOLVED complaint.
2bfaa218b0