[PATCH] [ELF] Support --defsym option to define an absolute symbol.

[Shankar Kalpathi Easwaran]

  I am not sure if you have seen this thread on lld --defsym option, it's more complicated than this to implement to reflect behavior like gnu ld.

  Note : the symbol gets defined in the output file only if there is a relocation to it or a reference to it. Any global symbol should still override defsym option.

  http://lists.cs.uiuc.edu/pipermail/llvmdev/2013-August/065094.html

http://llvm-reviews.chandlerc.com/D3208

BRANCH
  defsym

ARCANIST PROJECT
  lld