Add support for OpenSSL, mbedTLS 2 and mbedTLS 3

Brings the previous OpenSSL implementation into src/IO/tls_openssl.c.

Now, the TLS functions have the implementation name as prefix, like
a_Tls_openssl_connect().

The generic interface at IO/tls.h hides the implementation which is
selected at configure time. The appropriate functions of that
implementation are called from IO/tls.c to IO/tls_<impl>.c. In this way,
support for more TLS libraries can easily be added.

In the case of mbedTLS, there are some incompatible changes from version
2 to 3, so we use some ifdefs to fix the differences.

1 files changed, 2 insertions, 1 deletions

diff --git a/src/hsts.c b/src/hsts.c
index cc4d0dea..b11e9ffb 100644
--- a/src/hsts.c
+++ b/src/hsts.c
@@ -3,6 +3,7 @@
  * HTTP Strict Transport Security
  *
  * Copyright 2015 corvid
+ * Copyright (C) 2023 Rodrigo Arias Mallo <rodarima@gmail.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -195,7 +196,7 @@ static void Hsts_eat_value(const char **str)
  */
 void a_Hsts_set(const char *header, const DilloUrl *url)
 {
-   long max_age;
+   long max_age = 0;
    const char *host = URL_HOST(url);
    bool_t max_age_valid = FALSE, subdomains = FALSE;