* cygheap.h (struct _cmalloc_entry): Define b as unsigned rather than
	DWORD.
	(NBUCKETS): Define here as constant value.
	(struct init_cygheap): Add bucket_val member.  Define size of bucket_val
	and buckets using NBUCKETS.
	* cygheap.cc (NBUCKETS): Drop definition here.
	(cygheap_init): Initialize cygheap->bucket_val.  Add comment to explain
	what we do and why.
	(_cmalloc): Simplify bit bucket search using cygheap->bucket_val.  Drop
	local variable sz.  Fetch size of block from cygheap->bucket_val.
	(_cfree): Define b as unsigned.
	(_crealloc): Fetch size of block from cygheap->bucket_val.