changes in the tree for sparc boot disks

[Eric Delaunay <delaunay@lix.polytechnique.fr>]

Hello,

I commited some small changed to the main tree after I built sparc bootdisks.

Especially, I reworked the altkernel feature in the top Makefile to be more
generic.  It could allow all arch to build alternate bootdisks if they add
$(EXT) in the name of each rescue/drivers image and add altkver=x.y.z in the
same section kver is defined.

I also removed the step asking the user to choose bewteen local or GMT time for
the hardware clock if running on sparc.  If other arch want to do this as well,
they just need to remove #define LOCALTIME in dboostrap.h.

Others are bugfixes (choose_medium.c, extract_kernel.c).

Last of all, I disabled small libs for sparc it seems not to work :-(  I always
get the following message when booting from the newly generated disk:

init: error in loading shared libraries: init: symbol stdout, version GLIBC_2.0
not defined in file libc.so.6 with link time reference

I'm using egcc 2.91.60-5, binutils 2.9.5.0.12-2 and libc6 2.1.2-4 if it
matters.

Any pointers why it fails?

PS: I hope I didn't break anything.

-- 
 Eric Delaunay                 | "La guerre justifie l'existence des militaires.
 delaunay@lix.polytechnique.fr | En les supprimant." Henri Jeanson (1900-1970)