[compiler-rt] build compiler-rt runtimes without LTO
Summary: Currently, we build the compiler-rt runtimes with link-time optimization if LTO is configured for the LLVM project. This will break external programs that don't invoke the linker in such a way that it supports LLVM's LTO. To avoid this, this change causes the compiler-rt runtimes to be compiled with -fno-lto. This also makes the check-profile tests work on systems when doing a lld LTO build on a system where the system linker does not support LLVM LTO.
Reviewers: rnk, davidxl
Reviewed By: davidxl
Subscribers: dberris, mgorny, llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D31218
llvm-svn: 298525