Replace macros from stdint.h with literals to make code more generic

src/ssl.c

@@ -5728,7 +5728,7 @@ int wolfSSL_export_keying_material(WOLFSSL *ssl,
 
     /* Sanity check contextLen to prevent integer overflow when cast to word32
      * and to ensure it fits in the 2-byte length encoding (max 65535). */
-    if (use_context && contextLen > UINT16_MAX) {
+    if (use_context && contextLen > 0xFFFF) {
         WOLFSSL_MSG("contextLen too large");
         return WOLFSSL_FAILURE;
     }

src/tls13.c

@@ -1024,7 +1024,7 @@ int Tls13_Exporter(WOLFSSL* ssl, unsigned char *out, size_t outLen,
         return ret;
 
     /* Sanity check contextLen to prevent truncation when cast to word32. */
-    if (contextLen > UINT32_MAX) {
+    if (contextLen > 0xFFFFFFFFU) {
         return BAD_FUNC_ARG;
     }