The attached patch removes support for those versions of the compilers which are not capable of SFINAE.
This bumps the compiler requirement to remove support for Borland 5.x, Metrowerks prior to 9.0, and SunPro prior to 5.7. Compilers based on EDG 238 are also affected, though it is unknown what those are.
Ok to commit?
Please, wait for at least John give you permission.
It's OK by me, though as others have already said, best to wait for the 1.55 release to go out first... just in case we need to test patches/bug reports in Trunk. I suspect we've also reached the point where deprecating many more workarounds will likely cause a lot of flak once users figure out what we're doing. I guess in an ideal world, we would advertise what's being removed on the home page for 6 months or so before actually doing it. But I recognize that we may just need to move forward while we have a volunteer willing to do the work. Cheers, John.