This fixes a problem for 64-bit Cygwin, where building some packages can
produce spurious errors about truncated relocations.  The relocations are
only truncated because they are being made against sections which are going
to be discarded so that base address is zero instead of the expected 64-bit
base value.

	* cofflink.c (_bfd_coff_generic_relocate_section): Skip
	relocations in discarded sections.
Add support for %hi8, %hi16 and %lo16 being used when relocation are necessary.

	* config/tc-rl78.c (rl78_op): Issue an error message if a 16-bit
	relocation is used on an 8-bit operand or vice versa.
	(tc_gen_reloc): Use the RL78_16U relocation for RL78_CODE.
	(md_apply_fix): Add support for RL78_HI8, RL78_HI16 and RL78_LO16.