Summary:
Adds libc interceptors to the runtime library for the new
EfficiencySanitizer ("esan") family of tools. The interceptors cover
the memory operations in most common library calls and will be shared
among all esan tools.
Reviewers: aizatsky
Subscribers: zhaoqin, tberghammer, danalbert, srhines, llvm-commits, vitalybuka, eugenis, kcc
Differential Revision: http://reviews.llvm.org/D19411
llvm-svn: 267293