diff --git a/README.md b/README.md
index 74e4e62d..27c35a13 100644
--- a/README.md
+++ b/README.md
@@ -6033,7 +6033,7 @@ If the C11 implementation does not respect the C standard
 (i.e. the compiler targets C11 mode
 the  \_\_STDC\_NO\_THREADS\_\_ macro is not defined
 but the header threads.h is not available or not working),
-then the user shall define manually the \_\_STDC\_NO\_THREADS\_\_
+then the user shall define manually the M\_USE\_C11\_NO\_THREADS
 macro before including any M\*LIB header to disable it, so that
 M\*LIB can select another implementation.
 
diff --git a/m-mutex.h b/m-mutex.h
index 70abf308..9f1ba4ed 100644
--- a/m-mutex.h
+++ b/m-mutex.h
@@ -26,7 +26,8 @@
 #define MSTARLIB_MUTEX_H
 
 #if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L    \
-  && !defined(__STDC_NO_THREADS__)
+  && !defined(__STDC_NO_THREADS__)                              \
+  && !defined(M_USE_C11_NO_THREADS)
 
 /****************************** C11 version ********************************/