with the aim of making it more robust, more correct and perhaps faster.
This patch removes the need to poll blocking syscalls, by adding a proxy
LWP for each application thread. This LWP is a kernel thread whose job
is to run all (potentially) blocking syscalls, and also to handle signals.
This allows the kernel to do more of the work of dealing with signals,
so on kernels which do this properly (2.6), Valgrind's behavious is a
lot more posix compliant. On base 2.4 kernels, we emulate some of the
missing 2.6 functionality.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@1918
