kbuild fixes:
 o Do not use "-" in exported symbols, bash does not support that (Matthew/Keith)
 o Sort ALL_SUBDIRS, to avoid warning about duplicate target
	- Happens when the same directory are specified with drivers-y
	  and drivers-n
 o Added AWK, a few architectures actually use awk for normal compilation
 o Removed distclean from make help, now that distclean and mrporper are merged