This is the one remaining Polly install dirs related change that hasn't made it
into upstream yet; previously this patch file also included:
https://reviews.llvm.org/D117541

diff --git a/tools/polly/cmake/polly_macros.cmake b/tools/polly/cmake/polly_macros.cmake
index 518a09b45a42..bd9d6f5542ad 100644
--- a/tools/polly/cmake/polly_macros.cmake
+++ b/tools/polly/cmake/polly_macros.cmake
@@ -44,8 +44,8 @@ macro(add_polly_library name)
   if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY OR ${name} STREQUAL "LLVMPolly")
     install(TARGETS ${name}
       EXPORT LLVMExports
-      LIBRARY DESTINATION lib${LLVM_LIBDIR_SUFFIX}
-      ARCHIVE DESTINATION lib${LLVM_LIBDIR_SUFFIX})
+	  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX}
+      ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}${LLVM_LIBDIR_SUFFIX})
   endif()
   set_property(GLOBAL APPEND PROPERTY LLVM_EXPORTS ${name})
 endmacro(add_polly_library)