Try to skip some modules in freestanding mode

Author: ian-twilightcoder

stdlib/private/CMakeLists.txt

@@ -1,7 +1,9 @@
-if(SWIFT_BUILD_SDK_OVERLAY OR (SWIFT_BUILD_TEST_SUPPORT_MODULES AND NOT SWIFT_BUILD_DYNAMIC_SDK_OVERLAY_default))
+if(SWIFT_BUILD_SDK_OVERLAY OR (SWIFT_BUILD_TEST_SUPPORT_MODULES AND NOT SWIFT_BUILD_DYNAMIC_SDK_OVERLAY_default AND NOT SWIFT_FREESTANDING_FLAVOR STREQUAL "apple"))
   # SwiftPrivateThreadExtras makes use of Darwin/Glibc, which is part of the
   # SDK overlay. If the SDK overlay doesn't build by default, then it should
   # be available in the SDK and DifferentiationUnittest can still be built.
+  # However, the SDK overlay doesn't support freestanding, so still skip this
+  # in freestanding mode.
   if(SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING)
     add_subdirectory(DifferentiationUnittest)
   endif()
@@ -21,7 +23,7 @@ if(SWIFT_BUILD_SDK_OVERLAY OR SWIFT_BUILD_TEST_SUPPORT_MODULES)
   add_subdirectory(StdlibUnittest)
 endif()
 
-if(SWIFT_BUILD_SDK_OVERLAY OR (SWIFT_BUILD_TEST_SUPPORT_MODULES AND NOT SWIFT_BUILD_DYNAMIC_SDK_OVERLAY_default))
+if(SWIFT_BUILD_SDK_OVERLAY OR (SWIFT_BUILD_TEST_SUPPORT_MODULES AND NOT SWIFT_BUILD_DYNAMIC_SDK_OVERLAY_default AND NOT SWIFT_FREESTANDING_FLAVOR STREQUAL "apple"))
   add_subdirectory(OSLog)
 
   if(CMAKE_SYSTEM_NAME STREQUAL "Darwin")