Add some C99 stdio.h numbers to compare with GLib on platforms
(such as Windows) where they use different implementations.
Add a wmem string test with NULL allocator, to compare wmem and GLib
performance with roughly the same memory allocation.
Use the block allocator as being more representative of normal
wmem performance, instead of using strict, that is normally
used for wmem debugging.
These are not pass/fail tests, so the automation cannot
validate them. They just slow down the CI builds. To
enable pass -m perf.
I think the --verbose comment is wrong, I did not detect
any difference in output with or without --verbose.
Because we already have the length of the output string after
calling vsnprintf(), we should avoid calling wmem_strdup(), which
will ignore that and recompute the length.
Increase the buffer size to a value that seems reasonable to
minimize the chance of a second call to vsnprintf().
This allows wmem to be used from other libraries, namely wsutil.
It is often the case that a funtion exists in wsutil and cannot
be used with a wmem scope, requiring some code duplication or
extra memory allocations, or vice-versa, code in epan cannot be
moved to wsutil because it has a wmem dependency.
To this end wmem is moved to wsutil. Scope management remains part
of epan because those scope semantics are specific to dissection.