Changes in uml-2.4.18-22-sparc64-1

- Changed top-level Makefile to point to sparc64-linux Cross-compiler.
- Added checksum.h and removed arch-signal.h from SYMLINK_HEADERS in
arch/um/Makefile. Also changed the linux: entry to include CFLAGS and
gcc-3.0.4 specific bits, to help it to compile.
- Added Makefile-sparc64.
- Added arch/um/include/sysdep-sparc64 dir with files frame.h,
frame_kern.h, frame_user.h, ptrace.h, ptrace_user.h,sc.h, sigcontext.h
and syscalls.h.

- Changed arch/um/kernel/Makefile linker options to force 64-bit build.
- Commented out entries for PT_REGS_IP and PT_REGS_SP(which are i386
specific) in frame_kern.c.
- Modified irq.c to undef disable_irq_nosync.
- Commented out lines for SA_NODEFER and SA_RESTORER macros in
signal_kern.c
- Commented out syscalls in sys_call_table.c and syscall_kern.c that are
not implemented in linux/Sparc.
- Modified time_kern.c to include a Sparc64 specific delay loop.

- Added arch/um/sys-sparc64 dir with files Makefile, ksyms.c,
memstuff.c(which includes stubs for mem functions that are not
implemented on Sparc64), misc.c(Miscellaneous functions that need
Sparc64 specific implementation), ptrace.c, ptrace_user.c and
sigcontext.c in it.
- Modified include/asm-sparc64/checksum.h and page.h to comment out
definition for "cur_ds" pointer and undef (virt_to_phys, phys_to_virt)
macros respectively.
- Also in include/asm-sparc64/unistd.h, commented out some macros.

-Added archparam-sparc64.h, checksum-generic.h, checksum-sparc64.h,
elf-sparc64.h, processor-sparc64.h, ptrace-sparc64.h,
sigcontext-sparc64.h, system-sparc64.h and modified page.h