Create CMakeLibTests output dir for Xcode

Xcode 2.x forgets to create the target output directory before linking
the individual architecture pieces of a universal binary for the target
CMakeLibTests.  Then it passes the directory to -L and -F options when
linking the and warns that the directory does not exist.  We work around
the problem by using a pre-build rule on the target to create the output
directory.

Tests/CMakeLib/CMakeLists.txt

@@ -17,6 +17,16 @@ create_test_sourcelist(CMakeLib_TEST_SRCS CMakeLibTests.cxx ${CMakeLib_TESTS})
 add_executable(CMakeLibTests ${CMakeLib_TEST_SRCS})
 target_link_libraries(CMakeLibTests CMakeLib)
 
+# Xcode 2.x forgets to create the output directory before linking
+# the individual architectures.
+if(CMAKE_OSX_ARCHITECTURES AND XCODE
+    AND NOT "${XCODE_VERSION}" MATCHES "^[^12]")
+  add_custom_command(
+    TARGET CMakeLibTests
+    PRE_BUILD COMMAND ${CMAKE_COMMAND} -E make_directory "${CMAKE_CFG_INTDIR}"
+    )
+endif()
+
 foreach(test ${CMakeLib_TESTS})
   add_test(CMakeLib.${test} CMakeLibTests ${test})
 endforeach()