Move Runtime libcall definitions to a .def file

This will allow eliminating the duplication of the names, and allow adding
extra information such as signatures in a future commit.

Differential Revision: https://reviews.llvm.org/D35522

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@308531 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed