Backport BOOST_ENABLE_THREADS/BOOST_DISABLE_THREADS fix for GCC 4.7. https://svn.boost.org/trac/boost/ticket/6165
Backport BOOST_ENABLE_THREADS/BOOST_DISABLE_THREADS fix for GCC 4.7.
https://svn.boost.org/trac/boost/ticket/6165

clemensg/passenger,pkmiec/passenger,cgvarela/passenger,clemensg/passenger,cgvarela/passenger,phusion/passenger,pkmiec/passenger,pkmiec/passenger,jawj/passenger,phusion/passenger,antek-drzewiecki/passenger,clemensg/passenger,phusion/passenger,antek-drzewiecki/passenger,bf4/passenger,antek-drzewiecki/passenger,jawj/passenger,kewaunited/passenger,bf4/passenger,bf4/passenger,antek-drzewiecki/passenger,cgvarela/passenger,jawj/passenger,kewaunited/passenger,jawj/passenger,phusion/passenger,bf4/passenger,cgvarela/passenger,kewaunited/passenger,cgvarela/passenger,kewaunited/passenger,antek-drzewiecki/passenger,antek-drzewiecki/passenger,kewaunited/passenger,pkmiec/passenger,phusion/passenger,kewaunited/passenger,antek-drzewiecki/passenger,clemensg/passenger,clemensg/passenger,cgvarela/passenger,kewaunited/passenger,phusion/passenger,pkmiec/passenger,bf4/passenger,cgvarela/passenger,phusion/passenger,pkmiec/passenger,kewaunited/passenger,phusion/passenger,clemensg/passenger,clemensg/passenger,bf4/passenger,jawj/passenger,pkmiec/passenger,jawj/passenger,jawj/passenger,cgvarela/passenger,bf4/passenger,clemensg/passenger,antek-drzewiecki/passenger