I started looking at this code because the nm in GNU
binutils was ignoring the first symbol in the .symtab
section.  Apparently, the System V ABI reserves the
first entry and requires all fields inside to be set
to zero.

The list of changes is as follows:

  · reserve the first symbol entry (as noted above)
  · fix the section indices for .data and .bss symbols
  · factor out common code for Elf32 and Elf64
  · remove the special case for elfsymo in [568]l/asm.c:/^asmb
  · add the "etext" symbol in 6l
  · add static symbols

R=rsc
CC=golang-dev
https://golang.org/cl/4524075