Change .obj to .$(O) in all dependencies.

Change .obj to .$(O) in all dependencies.
($(BLD)/casefiddle.$(O)): Remove compile command.
($(BLD)/gmalloc.$(O)): Remove compile command.
($(BLD)/dispnew.obj):
($(BLD)/keyboard.obj):
($(BLD)/w32inevt.obj):
($(BLD)/w32bdf.obj):
($(BLD)/alloc.obj):
($(BLD)/buffer.obj):
($(BLD)/editfns.obj):
($(BLD)/emacs.obj):
($(BLD)/fileio.obj):
($(BLD)/fns.obj):
($(BLD)/indent.obj):
($(BLD)/insdel.obj):
($(BLD)/intervals.obj):
($(BLD)/minibuf.obj):
($(BLD)/print.obj):
($(BLD)/scroll.obj):
($(BLD)/sysdep.obj):
($(BLD)/textprop.obj):
($(BLD)/widget.obj):
($(BLD)/xdisp.obj): Add dependency on w32gui.h.
($(BLD)/term.obj): Add dependency on dispextern.h.