--- libmalloc/libmalloc-521.120.7/xcodeconfig/libmalloc_common.xcconfig
+++ libmalloc/libmalloc-646.40.3/xcodeconfig/libmalloc_common.xcconfig
@@ -14,6 +14,7 @@
 CLANG_WARN_CONSTANT_CONVERSION = YES
 CLANG_WARN_EMPTY_BODY = YES
 CLANG_WARN_ENUM_CONVERSION = YES
+CLANG_WARN_IMPLICIT_FALLTHROUGH = YES
 CLANG_WARN_INFINITE_RECURSION = YES
 CLANG_WARN_INT_CONVERSION = YES
 CLANG_WARN_SUSPICIOUS_MOVE = YES