[PATCH] [ELF] Add two new virtual functions to the `OutputELFWriter` class to control dynamic symbol table populating and DT_NEEDED tag creation

[Rui Ueyama]

LGTM with a nit.

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Comment at: lib/ReaderWriter/ELF/Mips/MipsTargetHandler.h:70
@@ +69,3 @@
+    if (const auto *da = dyn_cast<DefinedAtom>(atom))
+      for (const auto *ref : *da) {
+        if (const auto *sla = dyn_cast<SharedLibraryAtom>(ref->target()))
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nit: s/auto/Reference/

http://reviews.llvm.org/D4255