harmonize include protection style

[Manfred Weis <manfredweis@…>]

there are different styles of encoding filenames in use in include protection the most common style is BOOST_<capitalized filename>_HPP

examples for deviations from that pattern are

any.hpp:

#ifndef BOOST_ANY_INCLUDED

thread.hpp:

#if !defined(BOOST_THREAD_WEK01082003_HPP)

concept_check.hpp: uses a pluralized filename

#ifndef BOOST_CONCEPT_CHECKS_HPP

throw_exception.hpp:

#ifndef BOOST_THROW_EXCEPTION_HPP_INCLUDED

wave.hpp:

#if !defined(WAVE_HPP_DCA0EA51_EF5B_4BF1_88A8_461DBC5F292B_INCLUDED)

the motivation for harmonizing include protection is to be able to conclude from the filename the guarding definition; that might be useful for checking whether certain files have been included.

[Steven Watanabe]

Might be useful??

As far as I am concerned, #include guards are the library author's business, as long as they are sufficiently mangled to be unique.