Support --with-openssl-argon2 on Windows

We change the error for ZTS builds to a warning, to not break snapshot
builds which automatically will try to enable OpenSSL password hashing.

We also change some messages to better fit building on Windows.

And of course, we cannot easily check whether `OSSL_set_max_threads()`
is actually available; instead we're looking up the function declaration
in its header file.

ext/openssl/config.w32

@@ -2,11 +2,22 @@
 
 ARG_WITH("openssl", "OpenSSL support", "no,shared");
 
+ARG_WITH("openssl-argon2", "OPENSSL: Enable argon2 password hashing (requires OpenSSL >= 3.2)", "no");
+
 if (PHP_OPENSSL != "no") {
 	var ret = SETUP_OPENSSL("openssl", PHP_OPENSSL);
 
 	if (ret >= 2) {
-		EXTENSION("openssl", "openssl.c xp_ssl.c");
+		EXTENSION("openssl", "openssl.c openssl_pwhash.c xp_ssl.c");
 		AC_DEFINE("HAVE_OPENSSL_EXT", 1, "Define to 1 if the PHP extension 'openssl' is available.");
+		if (PHP_OPENSSL_ARGON2 != "no") {
+			if (PHP_ZTS != "no") {
+				WARNING("OpenSSL argon2 hashing not supported in ZTS mode for now");
+			} else if (!CHECK_FUNC_IN_HEADER("openssl/thread.h", "OSSL_set_max_threads", PHP_PHP_BUILD + "\\include")) {
+				WARNING("OpenSSL argon2 hashing requires OpenSSL >= 3.2");
+			} else {
+				AC_DEFINE("HAVE_OPENSSL_ARGON2", 1, " Define to 1 to enable OpenSSL argon2 password hashing");
+			}
+		}
 	}
 }