[boost] config with cygwin

Subject: [boost] config with cygwin
From: Robert Ramey (ramey_at_[hidden])
Date: 2010-06-10 18:33:31

I've recently upgraded to the lastest version of Cygwin and found that
this current version supports wchar_t, wstring, etc

This section from config/platform/cygwin is now creating problems.

// cygwin specific config options:
#define BOOST_PLATFORM "Cygwin"
#define BOOST_NO_CWCHAR
#define BOOST_NO_CWCTYPE
#define BOOST_NO_SWPRINTF
#define BOOST_HAS_DIRENT_H
#define BOOST_HAS_LOG1P
#define BOOST_HAS_EXPM1

as it conflits with the following from config/stdlib/libstdcp3

#if !defined(_GLIBCPP_USE_WCHAR_T) && !defined(_GLIBCXX_USE_WCHAR_T)
# define BOOST_NO_CWCHAR
# define BOOST_NO_CWCTYPE
# define BOOST_NO_STD_WSTRING
# define BOOST_NO_STD_WSTREAMBUF
#endif

I've found that BOOST_NO_STD_WSTRING is NOT defined while
BOOST_NO_CWCHAR IS defined.  This is incorrect for the
latest version of cygwin - version 1.7.5 and likely previous versions.

I believe that config/platform/cygwin should be updated so that it looks 
like:

#define BOOST_PLATFORM "Cygwin"
#define BOOST_NO_SWPRINTF   // ? don't know about the rest of these
#define BOOST_HAS_DIRENT_H
#define BOOST_HAS_LOG1P
#define BOOST_HAS_EXPM1

according to the cygwin documentation - there is no place to retrieve
a version # for cygwin itself - only for specific packages.  So it would
seem that that's all we can/should do.

Robert Ramey