diff --git a/library/threading.c b/library/threading.c
index 2de117f..bae6644 100644
--- a/library/threading.c
+++ b/library/threading.c
@@ -19,7 +19,7 @@
 
 /*
  * Ensure gmtime_r is available even with -std=c99; must be defined before
- * config.h, which pulls in glibc's features.h. Harmless on other platforms.
+ * mbedtls_config.h, which pulls in glibc's features.h. Harmless on other platforms.
  */
 #if !defined(_POSIX_C_SOURCE)
 #define _POSIX_C_SOURCE 200112L