Merge revisions 14203,14574,14575 from the BUF_REMOVAL
branch to trunk.
This change eliminates the fixed size buffers in VG_(basename)
and VG_(dirname).


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14576 a5019735-40e9-0310-863c-91ae7b9d1cf9