Fix compiler warning with compiling on 32 bit

Fixes this compiler warning:

    vsnprintf.c:1074:43: warning: 'uqval' may be used uninitialized in this function [-Wmaybe-uninitialized]

vsnprintf.c

@@ -552,7 +552,7 @@ BSD_vfprintf(FILE *fp, const char *fmt0, va_list ap)
 #endif
 	u_long MAYBE_UNUSED(ulval) = 0; /* integer arguments %[diouxX] */
 #ifdef _HAVE_SANE_QUAD_
-	u_quad_t MAYBE_UNUSED(uqval); /* %q integers */
+	u_quad_t MAYBE_UNUSED(uqval) = 0; /* %q integers */
 #endif /* _HAVE_SANE_QUAD_ */
 	int base;		/* base for [diouxX] conversion */
 	int dprec;		/* a copy of prec if [diouxX], 0 otherwise */