Merge pull request #37 from jpf91/gdc-4.7

Sync GCC 4.7 branch with latest master
Make it harder for gcc to make wrong optimisations.
Split out toCtype, toElem, toIR.
Remove from d-glue.cc, update Makefile.
Update patches for latest gcc snapshot
Merge branch 'master' (early part) into gdc-4.7

Conflicts:
	gcc/d/Make-lang.in
        (the COMPILER->COMPILER_FOR_BUILD changes were already
         applied in gdc-4.7, but we use CXX_FOR_BUILD
         so that caused the merge conflict)
Merge branch 'master' into gdc-4.7