In some modes the compiler will emit a section for BSS symbols and
construct the values with labels, alignment and data instructions. This
change parses these sections and emits the local versions of each symbol
needed to make this work.
Change-Id: I8d43ffe4b5b734950aa4287a3dd7c0d2f191f2e4
Reviewed-on: https://boringssl-review.googlesource.com/15206
Reviewed-by: Adam Langley <agl@google.com>