syme.[ch]: Split syme->mask into two unsigned int fields.
The mask field indicates which properties on a field have been set, and
which have a local value.. The idea is that instead of all syme objects
having all SYFI_FIELD_LIMIT (22ish) possible fields, only non-default ones
are set.  locmask then indicates if a value is stored locally, and hasmask
indicates that the value has been set.  If set and not stored locally,
a per field default value is used.

Noticed that mask is ULong (64 bits on common architechtures), but the
bitwise arithmetic was all integer.. so, clearer to split the field into
two ints, and no increase in heap requirements.
genc.c: Remove optCleanStack option - it memsets the stack on all function
calls.  Not really needed, as we validate foam to check for unset
variables.
warning cleanup: showexports.c header files
warning cleanup: abquick.c: header files
tests: Add missing return statements to test_format.c
tests: test_printf has a stray strlen call.
warning cleanup: Header files in test_tfsat.c