This adds reproducible memory error and test-data
error injection, to the fuzzy-test framework.

This feature can be enabled with ./config -DERROR_INJECT
and additionally to enable call stacks -DERROR_CALLSTACK

If enable-asan is used, the callstack is printed by the
sanitizer, otherwise please set a breakpoint
at the function "break_here", which is executed each
time a memory allocation error is injected.

If called with the environment variable ERROR_INJECT
defined to the empty string the initialization value
is printed, and can be used to reproduce the failure
later, by passing the value to the ERROR_INJECT variable.

There is a search script that can be used to look
for errors, and print the command to reproduce the bug:

./testrun.sh

This runs in endless mode until an error is found.