re PR libstdc++/13045 (Demangler does demangle floating values.)

re PR libstdc++/13045 (Demangler does demangle floating values.)

PR libstdc++/13045
* bits/demangle.h
namespace __gnu_cxx::demangler
(enum substitution_nt): Removed trailing comma.
(implementation_details): Added.
(session<Allocator>::M_implementation_details): Added.
(session<Allocator>::session): Pass implementation_details.
(session<Allocator>::decode_encoding): Same.
(session<Allocator>::decode_real): Added.
(_GLIBCXX_DEMANGLER_STYLE_VOID _GLIBCXX_DEMANGLER_STYLE_LITERAL
_GLIBCXX_DEMANGLER_STYLE_LITERAL_INT
_GLIBCXX_DEMANGLER_STYLE_COMPACT_EXPR_OPS
_GLIBCXX_DEMANGLER_STYLE_SIZEOF_TYPENAME): Replaced with
implementation_details equivalent.
(session<Allocator>::decode_expression):
Use M_implementation_details instead of macros. Add extra parentheses
around 'larger than' operator in expressions in template arguments.
(session<Allocator>::decode_bare_function_type): Idem.
(session<Allocator>::decode_literal):
Idem, and call decode_real for floating literals.
(session<Allocator>::decode_type_with_postfix): Put the postfix
of the return type of (member) functions after the function
instead of after the return type.  Also, put a space after the
prefix of qualified function pointers: "int (* const<space>".
* src/demangle.cc: include most dependent header file first.
* testsuite/demangle/regression/cw-16.cc: Updated two
and added three tests.

From-SVN: r74304