Suppress msvc warnings.
Refs #3686.

[SVN r57996]
Remove obsolete MSVC check from pragma guard

 git grep -h -B1 "^#\s*pragma once" | grep -v pragma | sort | uniq

is now clean.

[SVN r85952]
Foreach: Remove obsolete MSVC version checks.

[SVN r86021]
Foreach: Remove use of obsolete GCC version check.

[SVN r86058]