templated bitwise operators

[c.]

Hi,

this changeset:

changeset:   14631:57e4ff70b7c1
user:        Jordi Gutiérrez Hermoso <address@hidden>
date:        Sun May 13 21:17:19 2012 -0400
summary:     Use more templates in bitwise operators. Death to macros! ☠


introduced use of std::bit_and<T>, std::bit_or<T>, etc. which were introduced 
in gcc only in version 4.3.
but I'm stuck with 4.2.1 on my system so that breaks the build for me ...

would it be OK to add a configure check to go back to the macro-based version 
if any of those templates is undefined?

if this is OK I'll prepare a changeset.

c.