Call `set disable-randomization off` only if it seems to be supported.
The goal is to neither get an error about disable-randomization not
being supported (e.g. on FreeBSD), nor get an error if it is supported
but fails (e.g. on Ubuntu).
Only fiddle with disable-randomization from all.sh, which cares
because it reports the failure of ASLR disabling as an error. If a
developer invokes the Gdb script manually, a warning about ASLR
doesn't matter.
We don't need to disable ASLR, so don't try. If gdb tries but fails,
the test runs normally, but all.sh then trips up because it sees
`warning: Error disabling address space randomization: Operation not permitted`
and interprets it as an error that indicates a test failure.
Improve the position of the breakpoint to be set at a line of code that
is less likely to be optimised out by the compiler. Setting the breakpoint
at a place that can be easily optimised out by the compiler will cause the
gdb script to fail as it cannot match the source code line to the
compiled code. For this reason the breakpoint is now set at the fclose()
call which is very unlikely to be optimised out or there might be a
resource leak.
The gdb script loads the programs/test/zeroize program and feeds it as
imput its own source code. Then sets a breakpoint just before the last
program's return code and checks that every element in memory was
zeroized. Otherwise it signals a failure and terminates.
The test was added to all.sh.
