diff --git a/compiler-rt/lib/scudo/standalone/include/scudo/interface.h b/compiler-rt/lib/scudo/standalone/include/scudo/interface.h
--- a/compiler-rt/lib/scudo/standalone/include/scudo/interface.h
+++ b/compiler-rt/lib/scudo/standalone/include/scudo/interface.h
@@ -120,7 +120,7 @@
 
 // Tune the allocator's choice of memory tags to make it more likely that
 // a certain class of memory errors will be detected. The value argument should
-// be one of the enumerators of the scudo_memtag_tuning enum below.
+// be one of the M_MEMTAG_TUNING_* constants below.
 #ifndef M_MEMTAG_TUNING
 #define M_MEMTAG_TUNING -102
 #endif
@@ -145,13 +145,15 @@
 #define M_TSDS_COUNT_MAX -202
 #endif
 
-enum scudo_memtag_tuning {
-  // Tune for buffer overflows.
-  M_MEMTAG_TUNING_BUFFER_OVERFLOW,
+// Tune for buffer overflows.
+#ifndef M_MEMTAG_TUNING_BUFFER_OVERFLOW
+#define M_MEMTAG_TUNING_BUFFER_OVERFLOW 0
+#endif
 
-  // Tune for use-after-free.
-  M_MEMTAG_TUNING_UAF,
-};
+// Tune for use-after-free.
+#ifndef M_MEMTAG_TUNING_UAF
+#define M_MEMTAG_TUNING_UAF 1
+#endif
 
 } // extern "C"