Make header files compilable by itself to get two benefits:
- never have to worry about order of inclusion
- never have to figure out hidden dependencies in order to be
  able to include a file


git-svn-id: svn://svn.valgrind.org/vex/trunk@2546 8f6e269a-dfd6-0310-a8e1-e2731360e62c
23 files changed