Make async-style syscalls work on ppc64, by using rt_sigprocmask
instead of sigprocmask.

In the process, discover that error handling for
ML_(do_syscall_for_client_WRK) on all platforms has always been
broken, in the sense that the sigprocmasks (which are important) could
silently fail.  This commit fixes that up too (only on ppc64-linux at
the moment, so all other platforms are probably broken now).



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@5407 a5019735-40e9-0310-863c-91ae7b9d1cf9
2 files changed