Index: llvm/utils/TableGen/Basic/CMakeLists.txt
--- llvm/utils/TableGen/Basic/CMakeLists.txt.orig
+++ llvm/utils/TableGen/Basic/CMakeLists.txt
@@ -24,6 +24,8 @@ add_llvm_library(LLVMTableGenBasic OBJECT EXCLUDE_FROM
   VTEmitter.cpp
 )
 
+add_definitions(-D_LIBCPP_USE_LOWER_DEQUE_BLOCK_SIZE)
+
 # Users may include its headers as "Basic/*.h"
 target_include_directories(LLVMTableGenBasic
   INTERFACE
