Index: cmake/Modules/CompilerRTUtils.cmake
===================================================================
--- cmake/Modules/CompilerRTUtils.cmake
+++ cmake/Modules/CompilerRTUtils.cmake
@@ -222,6 +222,16 @@
     set(COMPILER_RT_DEFAULT_TARGET_TRIPLE ${COMPILER_RT_TEST_TARGET_TRIPLE})
   endif()
 
+  if(NOT APPLE)
+    # Much of the non-darwin compiler-rt build assumes that
+    # COMPILER_RT_DEFAULT_TARGET_TRIPLE is the default target of the compiler
+    # being used. That isn't always a safe assumption, but adding this here makes
+    # it all work.
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} --target=${COMPILER_RT_DEFAULT_TARGET_TRIPLE}")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} --target=${COMPILER_RT_DEFAULT_TARGET_TRIPLE}")
+    set(CMAKE_ASM_FLAGS "${CMAKE_ASM_FLAGS} --target=${COMPILER_RT_DEFAULT_TARGET_TRIPLE}")
+  endif()
+
   string(REPLACE "-" ";" TARGET_TRIPLE_LIST ${COMPILER_RT_DEFAULT_TARGET_TRIPLE})
   list(GET TARGET_TRIPLE_LIST 0 COMPILER_RT_DEFAULT_TARGET_ARCH)
   list(GET TARGET_TRIPLE_LIST 1 COMPILER_RT_DEFAULT_TARGET_OS)