[PATCH] Make MCAsmParserSemaCallback::LookupInlineAsmLabel a pure virtual function

[Ehsan Akhgari]

>>! In D5432#4, @rnk wrote:
> Thanks, feel free to commit these kinds of improvements without pre-commit review at your discretion.

Will do, thanks!

REPOSITORY
  rL LLVM

http://reviews.llvm.org/D5432