ecoff2asm and ecoffcmp

The Net Yaroze library and SDK objects are ECOFF, a format current binutils no longer links. ecoff2asm converts ECOFF objects and archives to GNU as source, along with an ld script of PROVIDE definitions for every absolute symbol, which is how the libps entry points are described. ecoffcmp checks the conversion: it assembles the output and compares its .text against the original word by word, masking only the immediate fields where ECOFF and ELF keep relocation addends in different places.