Warnings regarding errata fixed and mapping symbol missing

[Han Shen]

Hi Cary,

Now our customers are able to run arm-gold and aarch64-gold with all
necessary errata fixes (thanks for the review). Now the next problem
is that gold report warnings regarding errata being fixed and mapping
symbols being missing, since Android/Chrome build script treats
warnings as errors, the warnings are annoying. Also one justification
for silencing them is that bfd gives no warning for such at all.
(Actually we chrome land has a local patch for 2.24/2.25 that disables
missing mapping symbols warning.)

I don't know if this had been discussed before, but is there an option
to silence these 2 warnings for gold? If not, could we add options to
silence these 2 warnings? What do you think?

-- 
Han Shen