diff --git a/Tests/Architecture/CMakeLists.txt b/Tests/Architecture/CMakeLists.txt
index bc767fe3d..927ce3fed 100644
--- a/Tests/Architecture/CMakeLists.txt
+++ b/Tests/Architecture/CMakeLists.txt
@@ -1,6 +1,32 @@
 cmake_minimum_required(VERSION 2.8)
 project(Architecture C)
 
+function(test_for_xcode4 result_var)
+  set(${result_var} 0 PARENT_SCOPE)
+  if(APPLE)
+    execute_process(COMMAND xcodebuild -version
+      OUTPUT_VARIABLE ov RESULT_VARIABLE rv
+      )
+    if("${rv}" STREQUAL "0")
+      if(ov MATCHES "^Xcode 4.[0-9].*$")
+        set(${result_var} 1 PARENT_SCOPE)
+      endif()
+    endif()
+  endif()
+endfunction()
+
+test_for_xcode4(is_xcode4)
+
+set(arch0 i386)
+set(arch1 ppc)
+
+if(is_xcode4)
+  # Xcode 4, use modern architectures as defaults
+  # Arch 'ppc' no longer works: tools no longer available starting with Xcode 4
+  set(arch0 i386)
+  set(arch1 x86_64)
+endif()
+
 add_library(foo foo.c)
 if(CMAKE_OSX_ARCHITECTURES)
   get_property(archs TARGET foo PROPERTY OSX_ARCHITECTURES)
@@ -10,12 +36,24 @@ if(CMAKE_OSX_ARCHITECTURES)
       "Expected [${CMAKE_OSX_ARCHITECTURES}], got [${archs}]."
       )
   endif()
+  list(LENGTH archs archs_len)
+  if(archs_len GREATER 1)
+    list(GET archs 0 arch0)
+    list(GET archs 1 arch1)
+  endif()
 endif()
-set_property(TARGET foo PROPERTY OSX_ARCHITECTURES i386)
-set_property(TARGET foo PROPERTY OSX_ARCHITECTURES_DEBUG ppc)
+
+message("is_xcode4='${is_xcode4}'")
+message("archs='${archs}'")
+message("arch0='${arch0}'")
+message("arch1='${arch1}'")
+
+set_property(TARGET foo PROPERTY OSX_ARCHITECTURES ${arch0})
+set_property(TARGET foo PROPERTY OSX_ARCHITECTURES_DEBUG ${arch1})
 
 add_executable(bar bar.c)
 target_link_libraries(bar foo)
+
 set_property(TARGET bar PROPERTY OUTPUT_NAME Architecture)
-set_property(TARGET bar PROPERTY OSX_ARCHITECTURES ppc)
-set_property(TARGET bar PROPERTY OSX_ARCHITECTURES_DEBUG i386)
+set_property(TARGET bar PROPERTY OSX_ARCHITECTURES ${arch1})
+set_property(TARGET bar PROPERTY OSX_ARCHITECTURES_DEBUG ${arch0})
diff --git a/Tests/BuildDepends/Project/CMakeLists.txt b/Tests/BuildDepends/Project/CMakeLists.txt
index 70a2f3701..a977884c9 100644
--- a/Tests/BuildDepends/Project/CMakeLists.txt
+++ b/Tests/BuildDepends/Project/CMakeLists.txt
@@ -1,9 +1,30 @@
 cmake_minimum_required(VERSION 2.6)
 project(testRebuild)
+
+function(test_for_xcode4 result_var)
+  set(${result_var} 0 PARENT_SCOPE)
+  if(APPLE)
+    execute_process(COMMAND xcodebuild -version
+      OUTPUT_VARIABLE ov RESULT_VARIABLE rv
+      )
+    if("${rv}" STREQUAL "0")
+      if(ov MATCHES "^Xcode 4.[0-9].*$")
+        set(${result_var} 1 PARENT_SCOPE)
+      endif()
+    endif()
+  endif()
+endfunction()
+
 if(APPLE)
   # only use multi-arch if the sysroot exists on this machine
   if(EXISTS "${CMAKE_OSX_SYSROOT}")
     set(CMAKE_OSX_ARCHITECTURES "ppc;i386")
+    test_for_xcode4(is_xcode4)
+    if(is_xcode4)
+      # Xcode 4, use modern architectures as defaults
+      # Arch 'ppc' no longer works: tools no longer available starting with Xcode 4
+      set(CMAKE_OSX_ARCHITECTURES i386 x86_64)
+    endif()
   endif(EXISTS "${CMAKE_OSX_SYSROOT}")
 endif(APPLE)