"clang++ hello.cc --rtlib=compiler-rt"
now can works without specifying additional unwind or exception
handling libraries.
This reworked version of the feature no longer modifies today's default
unwind library for compiler-rt: which is nothing. Rather, a user
can specify -DCLANG_DEFAULT_UNWINDLIB=libunwind when configuring
the compiler.
This should address the issues from the previous version.
Update tests for new --unwindlib semantics.
Differential Revision: https://reviews.llvm.org/D59109
llvm-svn: 356508