Makefile.am changes for AIX5. Almost all boilerplate stuff fitting in
with the existing factorisation scheme. The only change of interest
is that configure.in now generates automake symbols of name
VGP_platform and VGO_os, whereas previously it just made VG_platform
which was a bit inconsistent with the VGP/VGO/VGA scheme used in C
code.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@6242