Index: compiler-rt/trunk/CMakeLists.txt
===================================================================
--- compiler-rt/trunk/CMakeLists.txt
+++ compiler-rt/trunk/CMakeLists.txt
@@ -339,7 +339,7 @@
   # it, but CMake doesn't seem to have a way to set linker flags for
   # individual static libraries, so we enable the suppression flag for
   # the whole compiler-rt project.
-  append("/IGNORE:4221" CMAKE_STATIC_LINKER_FLAGS)
+  set(CMAKE_STATIC_LINKER_FLAGS "${CMAKE_STATIC_LINKER_FLAGS} /IGNORE:4221")
 endif()
 
 add_subdirectory(include)