diff --git a/csharp/src/Google.Protobuf/Reflection/FeatureSetDescriptor.g.cs b/csharp/src/Google.Protobuf/Reflection/FeatureSetDescriptor.g.cs
deleted file mode 100644
index 208ce1fcb6319..0000000000000
--- a/csharp/src/Google.Protobuf/Reflection/FeatureSetDescriptor.g.cs
+++ /dev/null
@@ -1,17 +0,0 @@
-#region Copyright notice and license
-// Protocol Buffers - Google's data interchange format
-// Copyright 2008 Google Inc.  All rights reserved.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file or at
-// https://developers.google.com/open-source/licenses/bsd
-#endregion
-
-namespace Google.Protobuf.Reflection;
-
-internal sealed partial class FeatureSetDescriptor
-{
-    // Canonical serialized form of the edition defaults, generated by embed_edition_defaults.
-    private const string DefaultsBase64 =
-        "ChMYhAciACoMCAEQAhgCIAMoATACChMY5wciACoMCAIQARgBIAIoATABChMY6AciDAgBEAEYASACKAEwASoAIOYHKOgH";
-}
diff --git a/src/google/protobuf/map.h b/src/google/protobuf/map.h
index 1f02abd21e776..3d65e7ca646a1 100644
--- a/src/google/protobuf/map.h
+++ b/src/google/protobuf/map.h
@@ -31,7 +31,8 @@
 #include "absl/memory/memory.h"
 #include "google/protobuf/message_lite.h"
 
-#if !defined(GOOGLE_PROTOBUF_NO_RDTSC) && defined(__APPLE__)
+#if !defined(GOOGLE_PROTOBUF_NO_RDTSC) && defined(__APPLE__) && \
+    (!defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE))
 #include <time.h>
 #endif
 
@@ -728,9 +729,10 @@ class PROTOBUF_EXPORT UntypedMapBase {
   map_index_t Seed() const {
     uint64_t s = 0;
 #if !defined(GOOGLE_PROTOBUF_NO_RDTSC)
-#if defined(__APPLE__)
+#if defined(__APPLE__) && \
+    (!defined(_POSIX_C_SOURCE) || defined(_DARWIN_C_SOURCE))
     // Use a commpage-based fast time function on Apple environments (MacOS,
-    // iOS, tvOS, watchOS, etc).
+    // iOS, tvOS, watchOS, etc), if we think the system headers expose it.
     s = clock_gettime_nsec_np(CLOCK_UPTIME_RAW);
 #elif defined(__x86_64__) && defined(__GNUC__)
     uint32_t hi, lo;