fix all the compile errors, leaving all warnings.

There is still things to do.


                       $ grep -n COMPILE *.[ch]
                       bitmap.c:1054:			/* COMPILE
                       bitmap.h:283:/* COMPILE */
                       md.c:4162:		/* COMPILE 
                       raid1.c:359:	/* COMPILE */
                       raid1.c:1694:			/* COMPILE */
                       raid1.c:2429:		/* COMPILE */

you could see the comments /*  COMPILE */ mark there, it means I am not sure how to modify it.
just leave it to next commits to fix it.