--- a/libstdc++-v3/include/c_global/cstdio
+++ b/libstdc++-v3/include/c_global/cstdio
@@ -140,7 +140,7 @@ namespace std
   using ::vsprintf;
 } // namespace
 
-#if _GLIBCXX_USE_C99
+#if _GLIBCXX_USE_C99 || defined __UCLIBC__
 
 #undef snprintf
 #undef vfscanf