[dwm] malloc'ed client in manage()

[Filippo Erik Negroni]

In manage(), we use calloc in order to initialise to all-zeros the newly
allocated Client structure object.

A preferable, safer and more portable way of achieving such initialisation
is to use the compiler's static initialisation.

Here is the change in manage():

-       Client *c, *t = NULL;
+       static Client czeroinit;
+       Client *c, *t = NULL;

-       if(!(c = calloc(1, sizeof(Client))))
-               die("fatal: could not calloc() %u bytes\n", sizeof(Client));
+       if(!(c = malloc(sizeof *c)))
+               die("fatal: out of memory\n");
+       *c = czeroinit;

-- 
Cheers,
Filippo