make boost.random use /dev/urandom

[Sebastian Mingramm <s.mingramm@…>]

The following stuff is applied by the gentoo ebuild for all boost
versions. It's supposed to make boost.random use /dev/urandom if
available. Please review and consider inclusion.

------------------------
# This enables building the boost.random library with /dev/urandom support
if [[ -e /dev/urandom ]] ; then
   mkdir -p libs/random/build
   cp "${FILESDIR}/random-Jamfile" libs/random/build/Jamfile.v2
   # yeah, we WANT it to work on non-Linux too
   sed -i -e 's/#ifdef __linux__/#if 1/' libs/random/random_device.cpp || die
fi
-------------------------
${FILESDIR}/random-Jamfile:
-------------------------
# Copyright (c) 2006 Tiziano Mueller
#
# Use, modification and distribution of the file is subject to the
# Boost Software License, Version 1.0.
# (See at http://www.boost.org/LICENSE_1_0.txt)


project boost/random
        : source-location ../ ;

SOURCES = random_device ;

lib boost_random
        : $(SOURCES).cpp 
        : <link>shared:<define>BOOST_RANDOM_DYN_LINK=1 ;
-------------------------

[Steven Watanabe]

(In [60199]) Rearrange the componenents in libs/random and create a library for random_device. Fixes #3672