In C++11 and C++14 any odr-use of these constants requires a definition
at namespace-scope. In C++17 they are implicitly inline and so the
namespace-scope redeclarations are redundant (and allowing them is
deprecated).
PR libstdc++/85098
* include/bits/regex.h [__cplusplus < 201703L] (basic_regex::icase)
(basic_regex::nosubs, basic_regex::optimize, basic_regex::collate)
(basic_regex::ECMAScript, basic_regex::basic, basic_regex::extended)
(basic_regex::awk, basic_regex::grep, basic_regex::egrep): Add
definitions.
* include/bits/regex_automaton.h (_NFA::_M_insert_state): Adjust
whitespace.
* include/bits/regex_compiler.tcc (__INSERT_REGEX_MATCHER): Add
braces around body of do-while.
* testsuite/28_regex/basic_regex/85098.cc: New
From-SVN: r260371
