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/Asynchronous/Expectations/main.swift b/Tests/Functional/Asynchronous/Expectations/main.swift
index 0fce781..bbf2742 100644
--- a/Tests/Functional/Asynchronous/Expectations/main.swift
+++ b/Tests/Functional/Asynchronous/Expectations/main.swift
@@ -340,11 +340,14 @@
 
     // PRAGMA MARK: - Interrupted Waiters
 
-// CHECK: Test Case 'ExpectationsTestCase.test_outerWaiterTimesOut_InnerWaitersAreInterrupted' started at \d+-\d+-\d+ \d+:\d+:\d+\.\d+
-// CHECK: .*[/\\]Tests[/\\]Functional[/\\]Asynchronous[/\\]Expectations[/\\]main.swift:[[@LINE+22]]: error: ExpectationsTestCase.test_outerWaiterTimesOut_InnerWaitersAreInterrupted : Asynchronous wait failed - Exceeded timeout of 0.1 seconds, with unfulfilled expectations: outer
-// CHECK: .*[/\\]Tests[/\\]Functional[/\\]Asynchronous[/\\]Expectations[/\\]main.swift:[[@LINE+11]]: error: ExpectationsTestCase.test_outerWaiterTimesOut_InnerWaitersAreInterrupted : Asynchronous waiter <XCTWaiter expectations: 'inner-1'> failed - Interrupted by timeout of containing waiter <XCTWaiter expectations: 'outer'>
-// CHECK: .*[/\\]Tests[/\\]Functional[/\\]Asynchronous[/\\]Expectations[/\\]main.swift:[[@LINE+15]]: error: ExpectationsTestCase.test_outerWaiterTimesOut_InnerWaitersAreInterrupted : Asynchronous waiter <XCTWaiter expectations: 'inner-2'> failed - Interrupted by timeout of containing waiter <XCTWaiter expectations: 'outer'>
-// CHECK: Test Case 'ExpectationsTestCase.test_outerWaiterTimesOut_InnerWaitersAreInterrupted' failed \(\d+\.\d+ seconds\)
+    // Disabled due to non-deterministic ordering of XCTWaiterDelegate callbacks, see [SR-10034] and <rdar://problem/49123061>
+/*
+    CHECK: Test Case 'ExpectationsTestCase.test_outerWaiterTimesOut_InnerWaitersAreInterrupted' started at \d+-\d+-\d+ \d+:\d+:\d+\.\d+
+    CHECK: .*[/\\]Tests[/\\]Functional[/\\]Asynchronous[/\\]Expectations[/\\]main.swift:[[@LINE+22]]: error: ExpectationsTestCase.test_outerWaiterTimesOut_InnerWaitersAreInterrupted : Asynchronous wait failed - Exceeded timeout of 0.1 seconds, with unfulfilled expectations: outer
+    CHECK: .*[/\\]Tests[/\\]Functional[/\\]Asynchronous[/\\]Expectations[/\\]main.swift:[[@LINE+11]]: error: ExpectationsTestCase.test_outerWaiterTimesOut_InnerWaitersAreInterrupted : Asynchronous waiter <XCTWaiter expectations: 'inner-1'> failed - Interrupted by timeout of containing waiter <XCTWaiter expectations: 'outer'>
+    CHECK: .*[/\\]Tests[/\\]Functional[/\\]Asynchronous[/\\]Expectations[/\\]main.swift:[[@LINE+15]]: error: ExpectationsTestCase.test_outerWaiterTimesOut_InnerWaitersAreInterrupted : Asynchronous waiter <XCTWaiter expectations: 'inner-2'> failed - Interrupted by timeout of containing waiter <XCTWaiter expectations: 'outer'>
+    CHECK: Test Case 'ExpectationsTestCase.test_outerWaiterTimesOut_InnerWaitersAreInterrupted' failed \(\d+\.\d+ seconds\)
+ */
     func test_outerWaiterTimesOut_InnerWaitersAreInterrupted() {
         let outerWaiter = XCTWaiter(delegate: self)
         let outerExpectation = XCTestExpectation(description: "outer")
@@ -495,7 +498,7 @@
             ("test_countedConditionFail", test_countedConditionFail),
 
             // Interrupted Waiters
-            ("test_outerWaiterTimesOut_InnerWaitersAreInterrupted", test_outerWaiterTimesOut_InnerWaitersAreInterrupted),
+//            ("test_outerWaiterTimesOut_InnerWaitersAreInterrupted", test_outerWaiterTimesOut_InnerWaitersAreInterrupted),
             ("test_outerWaiterCompletes_InnerWaiterTimesOut", test_outerWaiterCompletes_InnerWaiterTimesOut),
 
             // Waiter Conveniences
@@ -510,11 +513,11 @@
     }()
 }
 // CHECK: Test Suite 'ExpectationsTestCase' failed at \d+-\d+-\d+ \d+:\d+:\d+\.\d+
-// CHECK: \t Executed 31 tests, with 17 failures \(0 unexpected\) in \d+\.\d+ \(\d+\.\d+\) seconds
+// CHECK: \t Executed 30 tests, with 14 failures \(0 unexpected\) in \d+\.\d+ \(\d+\.\d+\) seconds
 
 XCTMain([testCase(ExpectationsTestCase.allTests)])
 
 // CHECK: Test Suite '.*\.xctest' failed at \d+-\d+-\d+ \d+:\d+:\d+\.\d+
-// CHECK: \t Executed 31 tests, with 17 failures \(0 unexpected\) in \d+\.\d+ \(\d+\.\d+\) seconds
+// CHECK: \t Executed 30 tests, with 14 failures \(0 unexpected\) in \d+\.\d+ \(\d+\.\d+\) seconds
 // CHECK: Test Suite 'All tests' failed at \d+-\d+-\d+ \d+:\d+:\d+\.\d+
-// CHECK: \t Executed 31 tests, with 17 failures \(0 unexpected\) in \d+\.\d+ \(\d+\.\d+\) seconds
+// CHECK: \t Executed 30 tests, with 14 failures \(0 unexpected\) in \d+\.\d+ \(\d+\.\d+\) seconds
diff --git a/Tests/Functional/Performance/main.swift b/Tests/Functional/Performance/main.swift
index 04ae8a0..aafa33a 100644
--- a/Tests/Functional/Performance/main.swift
+++ b/Tests/Functional/Performance/main.swift
@@ -65,7 +65,9 @@
     // CHECK: .*[/\\]Performance[/\\]main.swift:[[@LINE+3]]: Test Case 'PerformanceTestCase.test_printsValuesAfterMeasuring' measured \[Time, seconds\] average: \d+.\d{3}, relative standard deviation: \d+.\d{3}%, values: \[\d+.\d{6}, \d+.\d{6}, \d+.\d{6}, \d+.\d{6}, \d+.\d{6}, \d+.\d{6}, \d+.\d{6}, \d+.\d{6}, \d+.\d{6}, \d+.\d{6}\], performanceMetricID:org.swift.XCTPerformanceMetric_WallClockTime, maxPercentRelativeStandardDeviation: \d+.\d{3}%, maxStandardDeviation: \d.\d{3}
     // CHECK: Test Case 'PerformanceTestCase.test_printsValuesAfterMeasuring' passed \(\d+\.\d+ seconds\)
     func test_printsValuesAfterMeasuring() {
-        measure {}
+        measure {
+          Thread.sleep(forTimeInterval: 1)
+        }
     }
 
     // CHECK: Test Case 'PerformanceTestCase.test_abortsMeasurementsAfterTestFailure' started at \d+-\d+-\d+ \d+:\d+:\d+\.\d+
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'),
     ])