--- src/libANGLE/Context.cpp	2026-01-07 08:40:27.000000000 +0800
+++ src/libANGLE/Context.cpp	2026-01-11 03:25:32.000000000 +0800
@@ -64,7 +64,7 @@
 #include "libANGLE/validationES.h"
 
 #if defined(ANGLE_PLATFORM_APPLE)
-#    include <dispatch/dispatch.h>
+#    include <pthread.h>
 #    include "common/tls.h"
 #endif
 
@@ -609,15 +609,22 @@
 #if defined(ANGLE_PLATFORM_APPLE)
 // TODO(http://anglebug.com/42264979): Due to a bug in Apple's dyld loader, `thread_local` will
 // cause excessive memory use. Temporarily avoid it by using pthread's thread local storage instead.
+namespace
+{
+angle::TLSIndex g_CurrentValidContextIndex = TLS_INVALID_INDEX;
+pthread_once_t g_CurrentValidContextIndexOnce = PTHREAD_ONCE_INIT;
+
+void InitCurrentValidContextTLSIndex()
+{
+    ASSERT(g_CurrentValidContextIndex == TLS_INVALID_INDEX);
+    g_CurrentValidContextIndex = angle::CreateTLSIndex(nullptr);
+}
+} // anonymous namespace
+
 static angle::TLSIndex GetCurrentValidContextTLSIndex()
 {
-    static angle::TLSIndex CurrentValidContextIndex = TLS_INVALID_INDEX;
-    static dispatch_once_t once;
-    dispatch_once(&once, ^{
-      ASSERT(CurrentValidContextIndex == TLS_INVALID_INDEX);
-      CurrentValidContextIndex = angle::CreateTLSIndex(nullptr);
-    });
-    return CurrentValidContextIndex;
+    pthread_once(&g_CurrentValidContextIndexOnce, InitCurrentValidContextTLSIndex);
+    return g_CurrentValidContextIndex;
 }
 Context *GetCurrentValidContextTLS()
 {