gcc-4.5 build fixes

gcc-4.5 build fixes

Trying to build binutils with an older gcc currently fails.  Working
around these gcc bugs is not onerous so let's fix them.

bfd/
	* elf32-csky.c (csky_elf_size_dynamic_sections): Don't type-pun
	pointer.
	* elf32-rl78.c (rl78_compute_complex_reloc): Rename "stat"
	variable to "status".
gas/
	* compress-debug.c (compress_finish): Supply all fields in
	ZSTD_inBuffer initialisation.
include/
	* xtensa-dynconfig.h (xtensa_isa_internal): Delete unnecessary
	forward declaration.
opcodes/
	* loongarch-opc.c: Supply all fields of zero struct initialisation
	in various opcode tables.