Add an AppleInternal path to framework search paths

watchOS XCTest was temporarily moved to an AppleInternal path,
so we need to add it to the framework search path to continue to
build the watchOS overlay.

rdar://problem/20883853

Swift SVN r28353

Author: bitjammer

cmake/modules/AddSwift.cmake

@@ -68,6 +68,7 @@ function(_add_variant_c_compile_link_flags
     list(APPEND result
         "-arch" "${arch}"
         "-F" "${SWIFT_SDK_${sdk}_PATH}/../../../Developer/Library/Frameworks"
+        "-F" "${SWIFT_SDK_${sdk}_PATH}/../../../Developer/AppleInternal/Library/Frameworks"
         "-m${SWIFT_SDK_${sdk}_VERSION_MIN_NAME}-version-min=${SWIFT_SDK_${sdk}_DEPLOYMENT_VERSION}")
 
     append_darwin_segalign_link_flags("${arch}" result)
@@ -125,7 +126,8 @@ function(_add_variant_swift_compile_flags
 
   if("${CMAKE_SYSTEM_NAME}" STREQUAL "Darwin")
     list(APPEND result
-        "-F" "${SWIFT_SDK_${sdk}_PATH}/../../../Developer/Library/Frameworks")
+        "-F" "${SWIFT_SDK_${sdk}_PATH}/../../../Developer/Library/Frameworks"
+        "-F" "${SWIFT_SDK_${sdk}_PATH}/../../../Developer/AppleInternal/Library/Frameworks")
 
     append_darwin_segalign_link_flags("${arch}" result)
   endif()