libgcc fails to build for sh-elf toolchain

[Nick Clifton]

Hi Alex, Hi Kaz,

  The sh-elf target is currently failing to build libgcc on the FSF
  mainline because:

    libgcc/unwind-dw2.c: In function 'execute_stack_op':
    libgcc/unwind-dw2.c:902:1: error: unable to generate reloads for:

    (set (reg:SI 147 t)
         (zero_extract:SI (reg:SI 621 [ MEM[(struct _Unwind_Context 
*)context_25(D) + 640B] ])
                          (const_int 1)
                          (const_int 30)))

    libgcc/unwind-dw2.c:902:1: internal compiler error: in find_reloads, at 
reload.c:3879

  This bug has only shown up in the last few weeks - the toolchain was
  building OK at the end of November...
  
Cheers
  Nick