diff --git a/include/openssl/base.h b/include/openssl/base.h
index c0d7a8c5..10f6e413 100644
--- a/include/openssl/base.h
+++ b/include/openssl/base.h
@@ -65,6 +65,10 @@
 #include <stdio.h>
 #endif
 
+#if defined(__APPLE__)
+#include <TargetConditionals.h>
+#endif
+
 // Include a BoringSSL-only header so consumers including this header without
 // setting up include paths do not accidentally pick up the system
 // opensslconf.h.