build: adjust for new build layout

Moving CoreFoundation into the root is needed to actually get the proper
dependency tracking for Foundation builds. This adjusts the use of it
in XCTest.
diff --git a/CMakeLists.txt b/CMakeLists.txt
index dfa8eb9..be10f91 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -106,6 +106,7 @@
                     -Xcc -fblocks
 
                     -I${XCTEST_PATH_TO_FOUNDATION_BUILD}/swift
+                    -Fsystem ${XCTEST_PATH_TO_FOUNDATION_BUILD}
                     -Fsystem ${XCTEST_PATH_TO_COREFOUNDATION_BUILD}/System/Library/Frameworks
 
                     # compatibility with Foundation build_script.py
diff --git a/Tests/Functional/lit.cfg b/Tests/Functional/lit.cfg
index 9c38ebd..294fab5 100644
--- a/Tests/Functional/lit.cfg
+++ b/Tests/Functional/lit.cfg
@@ -85,6 +85,8 @@
         '-L', foundation_dir,
         '-I', foundation_dir,
         '-I', os.path.join(foundation_dir, 'swift'),
+        '-Xcc', '-F', '-Xcc', foundation_dir,
+
         '-I', core_foundation_dir,
         '-Xcc', '-F', '-Xcc', os.path.join(core_foundation_dir, 'System', 'Library', 'Frameworks'),
     ])