[boost] "Remove obsolete MSVC checks" and _MSC_VER

Subject: [boost] "Remove obsolete MSVC checks" and _MSC_VER
From: Peter Dimov (lists_at_[hidden])
Date: 2013-09-26 12:41:02

One general note about these changes. This:

#if defined( _MSC_VER ) && _MSC_VER >= 1310

doesn't mean "compiler is MS VC++ 7.1". It means "compiler claims to support 
MSVC 7.1's features." Many Windows compilers define _MSC_VER for 
compatibility.

I'm not positive that the removal of the _MSC_VER >= part would break 
something nowadays, but if it does, this would be why. I'd have left these 
alone; it's not clear what purpose removing the check is intended to serve, 
apart from breaking code.

Actual MSVC-specific code is guarded by BOOST_MSVC and not _MSC_VER.