[Bug sanitizer/59275] Document environment variables used by the sanitizers

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59275

--- Comment #2 from Tobias Burnus <burnus at gcc dot gnu.org> ---
Partial list for ASAN; linking to it might be an option:
  https://code.google.com/p/address-sanitizer/wiki/Flags#Run-time_flags

Seemingly, there is no list for LSAN/TSAN.

The URL above lists part of the common options, missing are:
  symbolize
  handle_ioctl
  detect_leaks
  leak_check_at_exit
  allocator_may_return_null
and most of the ASAN options, missing are
  allow_reexec
  atexit
  check_malloc_usable_size
  debug
  malloc_fill_byte
  max_malloc_fill_size
  poison_heap
  print_full_thread_history
  print_legend
  print_stats
  replace_intrin
  replace_str
  report_globals
  unmap_shadow_on_exit
  use_sigaltstack
  use_stack_depot