wmaker: moved the variable 'process_workspacemap_event' to the global namespace

wmaker: moved the variable 'process_workspacemap_event' to the global namespace

The definition in the local header was not correct; it works because gcc is
tolerant to this kind of errors but other compilers are not. The
declaration was creating a local variable in each file that call header,
and because it is not static gcc's linker will merge them. Other compilers
will at best complain for duplicate symbol, and at worst silently duplicate
the variable so it will not work as expected.

The variable is now moved to the existing structure meant for global
variables, so now the code is really clear about using a global variable
instead of a static/local one.

Took opportunity to add some missing 'static' attributes to some variables.

Signed-off-by: Christophe CURIS <christophe.curis@free.fr>