diff --git a/include/fmt/posix.h b/include/fmt/posix.h
index 2fb01260..c5e27e05 100644
--- a/include/fmt/posix.h
+++ b/include/fmt/posix.h
@@ -266,7 +266,7 @@ class file {
 long getpagesize();
 
 #if (defined(LC_NUMERIC_MASK) || defined(_MSC_VER)) && \
-    !defined(__ANDROID__) && !defined(__CYGWIN__) && !defined(__OpenBSD__)
+    !defined(__ANDROID__) && !defined(__CYGWIN__) && !defined(__OpenBSD__) && !defined(__NEWLIB_H__)
 # define FMT_LOCALE
 #endif