[CMake] Set per-runtime library directory suffix in runtimes build

Do not use LLVM_RUNTIMES_LIBDIR_SUFFIX variable which is an internal
variable used by the runtimes build from individual runtimes, instead
set per-runtime librarhy directory suffix variable which is necessary
for the sanitized runtimes build to install libraries into correct
location.

Differential Revision: https://reviews.llvm.org/D49121

git-svn-id: https://llvm.org/svn/llvm-project/libunwind/trunk@336713 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CMakeLists.txt b/CMakeLists.txt
index fc46764..704402d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -176,7 +176,7 @@
 
 if(LLVM_ENABLE_PER_TARGET_RUNTIME_DIR AND NOT APPLE)
   set(DEFAULT_INSTALL_PREFIX lib${LLVM_LIBDIR_SUFFIX}/clang/${CLANG_VERSION}/${LLVM_DEFAULT_TARGET_TRIPLE}/)
-  set(LIBUNWIND_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION}/${LLVM_DEFAULT_TARGET_TRIPLE}/lib${LLVM_RUNTIMES_LIBDIR_SUFFIX})
+  set(LIBUNWIND_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR}/clang/${CLANG_VERSION}/${LLVM_DEFAULT_TARGET_TRIPLE}/lib${LIBUNWIND_LIBDIR_SUFFIX})
 elseif(LLVM_LIBRARY_OUTPUT_INTDIR)
   set(LIBUNWIND_LIBRARY_DIR ${LLVM_LIBRARY_OUTPUT_INTDIR})
 else()