Index: runtimes/CMakeLists.txt
===================================================================
--- runtimes/CMakeLists.txt
+++ runtimes/CMakeLists.txt
@@ -228,10 +228,6 @@
       add_custom_target(builtins)
       add_custom_target(install-builtins)
       foreach(target ${LLVM_BUILTIN_TARGETS})
-        if(target STREQUAL "default")
-          set(target ${LLVM_DEFAULT_TARGET_TRIPLE})
-        endif()
-
         string(REPLACE "-" ";" builtin_target_list ${target})
         foreach(item ${builtin_target_list})
           string(TOLOWER "${item}" item_lower)
@@ -240,12 +236,21 @@
           endif()
         endforeach()
 
+        if(target STREQUAL "default")
+          set(target ${LLVM_DEFAULT_TARGET_TRIPLE})
+        endif()
+
         foreach(variableName ${variableNames})
           if(variableName MATCHES "^BUILTINS_${target}")
             string(REPLACE "BUILTINS_${target}_" "" new_name ${variableName})
             list(APPEND ${target}_extra_args "-D${new_name}=${${variableName}}")
           endif()
         endforeach()
+
+        if(NOT target STREQUAL LLVM_DEFAULT_TARGET_TRIPLE)
+          list(APPEND ${target}_extra_args "-DCOMPILER_RT_DEFAULT_TARGET_ONLY=ON")
+        endif()
+
         llvm_ExternalProject_Add(builtins-${target}
                                ${CMAKE_CURRENT_SOURCE_DIR}/compiler-rt/lib/builtins
                                CMAKE_ARGS -DLLVM_LIBRARY_OUTPUT_INTDIR=${LLVM_LIBRARY_DIR}
@@ -254,7 +259,6 @@
                                           -DCMAKE_ASM_COMPILER_TARGET=${target}
                                           -DCMAKE_C_COMPILER_WORKS=On
                                           -DCMAKE_ASM_COMPILER_WORKS=On
-                                          -DCOMPILER_RT_DEFAULT_TARGET_ONLY=On
                                           ${${target}_extra_args}
                                TOOLCHAIN_TOOLS clang lld llvm-ar llvm-ranlib
                                PASSTHROUGH_PREFIXES COMPILER_RT
@@ -340,7 +344,9 @@
     endforeach()
 
     if(NOT target STREQUAL LLVM_DEFAULT_TARGET_TRIPLE)
-      list(APPEND ${name}_extra_args "-DLLVM_RUNTIMES_TARGET=${name}")
+      list(APPEND ${name}_extra_args
+        "-DLLVM_RUNTIMES_TARGET=${name}"
+        "-DCOMPILER_RT_DEFAULT_TARGET_ONLY=ON")
     endif()
 
     llvm_ExternalProject_Add(runtimes-${name}
@@ -356,7 +362,6 @@
                                         -DCMAKE_C_COMPILER_WORKS=ON
                                         -DCMAKE_CXX_COMPILER_WORKS=ON
                                         -DCMAKE_ASM_COMPILER_WORKS=ON
-                                        -DCOMPILER_RT_DEFAULT_TARGET_ONLY=ON
                                         ${${name}_extra_args}
                              TOOLCHAIN_TOOLS clang lld llvm-ar llvm-ranlib
                              PASSTHROUGH_PREFIXES ${prefixes}