crypto: cast oaepLabel to unsigned char*

OpenSSL uses a macro without typechecking; since C++ does not
implicitly cast void* this is needed to conform Node.js to the
OpenSSL documentation.

PR-URL: #30917
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

src/node_crypto.cc

@@ -5512,8 +5512,9 @@ bool PublicKeyCipher::Cipher(Environment* env,
     // OpenSSL takes ownership of the label, so we need to create a copy.
     void* label = OPENSSL_memdup(oaep_label, oaep_label_len);
     CHECK_NOT_NULL(label);
-    if (0 >= EVP_PKEY_CTX_set0_rsa_oaep_label(ctx.get(), label,
-                                              oaep_label_len)) {
+    if (0 >= EVP_PKEY_CTX_set0_rsa_oaep_label(ctx.get(),
+                reinterpret_cast<unsigned char*>(label),
+                                      oaep_label_len)) {
       OPENSSL_free(label);
       return false;
     }