Tools should explain why an option is bad when using fmsg_bad_option.

Add an explanation of why an option was bad to fmsg_bad_option calls that
were just using "" as argument. Fixes bug #334802.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13975 a5019735-40e9-0310-863c-91ae7b9d1cf9
Revert configure support for adding -Werror=format-security.

This reverts part of valgrind svn r13962. There was a typo in the configure
check that caused failures when -Werror=format-security wasn't supported
and the flag interfered badly with -Wno-format-zero-length. So remove
for now and only add back when properly tested on various (older) setups.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13976 a5019735-40e9-0310-863c-91ae7b9d1cf9
On old kernel, poll syscall being ptraced (vgdb+ptrace) is not necessarily
properly restarted. Instead, it can fail with EINTR, even if no signal was
effectively received.

Handle such case by retrying the poll syscall when the poll syscall
is failing due to EINTR



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13977 a5019735-40e9-0310-863c-91ae7b9d1cf9
Revert "Tools should explain why an option is bad when using fmsg_bad_option."

This reverts valgrind svn r13975. This was a work in progress, still being
discussed in bug #334802. It should not yet been pushed.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13978 a5019735-40e9-0310-863c-91ae7b9d1cf9