diff --git a/demos/constants.c b/demos/constants.c
index 8f8f4aa3..ca1b1709 100644
--- a/demos/constants.c
+++ b/demos/constants.c
@@ -2,11 +2,8 @@
 /* SPDX-License-Identifier: Unlicense */
 #include "tomcrypt.h"
 
-#if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L
-#include <libgen.h>
-#else
-#define basename(x) x
-#endif
+#include <string.h>
+#define basename(path) ( strrchr((path), '/') ? strrchr((path), '/') + 1 : strrchr((path), '\\') ? strrchr((path), '\\') + 1 : (path) )
 
 /**
   @file demo_crypt_constants.c
diff --git a/demos/hashsum.c b/demos/hashsum.c
index dd129861..6789b656 100644
--- a/demos/hashsum.c
+++ b/demos/hashsum.c
@@ -12,11 +12,8 @@
 
 #include <tomcrypt.h>
 
-#if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L
-#include <libgen.h>
-#else
-#define basename(x) x
-#endif
+#include <string.h>
+#define basename(path) ( strrchr((path), '/') ? strrchr((path), '/') + 1 : strrchr((path), '\\') ? strrchr((path), '\\') + 1 : (path) )
 
 #if !defined(PATH_MAX) && defined(_MSC_VER)
 #include <windows.h>
diff --git a/demos/sizes.c b/demos/sizes.c
index 9d4bee58..c8406168 100644
--- a/demos/sizes.c
+++ b/demos/sizes.c
@@ -3,11 +3,9 @@
 
 #include "tomcrypt.h"
 
-#if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L
-#include <libgen.h>
-#else
-#define basename(x) x
-#endif
+#include <string.h>
+#define basename(path) ( strrchr((path), '/') ? strrchr((path), '/') + 1 : strrchr((path), '\\') ? strrchr((path), '\\') + 1 : (path) )
+
 /**
   @file demo_crypt_sizes.c