Import mbedtls-3.6.0

Imports Mbed TLS 3.6.0 from https://github.com/Mbed-TLS/mbedtls.git
tags mbedtls-3.6.0, v3.6.0

Files that are not needed are removed:

cd lib/libmbedtls
rm -rf mbedtls
cp -R path/to/mbedtls-3.6.0/mbedtls .
cd mbedtls
rm CMakeLists.txt DartConfiguration.tcl Makefile
rm .gitignore .travis.yml .pylintrc .globalrc .mypy.ini BRANCHES.md
rm include/.gitignore include/CMakeLists.txt library/.gitignore
rm library/CMakeLists.txt library/Makefile
rm -r cmake
rm -rf .git .github doxygen configs programs scripts tests visualc
rm -rf 3rdparty ChangeLog.d docs pkgconfig .gitmodules .readthedocs.yaml
rm library/mps_*
cd ..
git add mbedtls

This time we leave library/psa_* present to enable TLS 1.3 features.

This is a complete overwrite of previous code so earlier changes in the
previous branch import/mbedtls-3.4.0 will be added on top of this commit.

Signed-off-by: Tom Van Eyck <tom.vaneyck@kuleuven.be>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/lib/libmbedtls/mbedtls/library/entropy_poll.c b/lib/libmbedtls/mbedtls/library/entropy_poll.c
index b5024c8..794ee03 100644
--- a/lib/libmbedtls/mbedtls/library/entropy_poll.c
+++ b/lib/libmbedtls/mbedtls/library/entropy_poll.c
@@ -2,22 +2,10 @@
  *  Platform-specific and custom entropy polling functions
  *
  *  Copyright The Mbed TLS Contributors
- *  SPDX-License-Identifier: Apache-2.0
- *
- *  Licensed under the Apache License, Version 2.0 (the "License"); you may
- *  not use this file except in compliance with the License.
- *  You may obtain a copy of the License at
- *
- *  http://www.apache.org/licenses/LICENSE-2.0
- *
- *  Unless required by applicable law or agreed to in writing, software
- *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *  See the License for the specific language governing permissions and
- *  limitations under the License.
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
  */
 
-#if defined(__linux__) && !defined(_GNU_SOURCE)
+#if defined(__linux__) || defined(__midipix__) && !defined(_GNU_SOURCE)
 /* Ensure that syscall() is available even when compiling with -std=c99 */
 #define _GNU_SOURCE
 #endif
@@ -41,38 +29,40 @@
 
 #if !defined(unix) && !defined(__unix__) && !defined(__unix) && \
     !defined(__APPLE__) && !defined(_WIN32) && !defined(__QNXNTO__) && \
-    !defined(__HAIKU__) && !defined(__midipix__)
+    !defined(__HAIKU__) && !defined(__midipix__) && !defined(__MVS__)
 #error \
     "Platform entropy sources only work on Unix and Windows, see MBEDTLS_NO_PLATFORM_ENTROPY in mbedtls_config.h"
 #endif
 
 #if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
 
-#if !defined(_WIN32_WINNT)
-#define _WIN32_WINNT 0x0400
-#endif
 #include <windows.h>
-#include <wincrypt.h>
+#include <bcrypt.h>
+#include <intsafe.h>
 
 int mbedtls_platform_entropy_poll(void *data, unsigned char *output, size_t len,
                                   size_t *olen)
 {
-    HCRYPTPROV provider;
     ((void) data);
     *olen = 0;
 
-    if (CryptAcquireContext(&provider, NULL, NULL,
-                            PROV_RSA_FULL, CRYPT_VERIFYCONTEXT) == FALSE) {
-        return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
-    }
+    /*
+     * BCryptGenRandom takes ULONG for size, which is smaller than size_t on
+     * 64-bit Windows platforms. Extract entropy in chunks of len (dependent
+     * on ULONG_MAX) size.
+     */
+    while (len != 0) {
+        unsigned long ulong_bytes =
+            (len > ULONG_MAX) ? ULONG_MAX : (unsigned long) len;
 
-    if (CryptGenRandom(provider, (DWORD) len, output) == FALSE) {
-        CryptReleaseContext(provider, 0);
-        return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
-    }
+        if (!BCRYPT_SUCCESS(BCryptGenRandom(NULL, output, ulong_bytes,
+                                            BCRYPT_USE_SYSTEM_PREFERRED_RNG))) {
+            return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
+        }
 
-    CryptReleaseContext(provider, 0);
-    *olen = len;
+        *olen += ulong_bytes;
+        len -= ulong_bytes;
+    }
 
     return 0;
 }
@@ -98,7 +88,7 @@
     memset(buf, 0, buflen);
 #endif
 #endif
-    return syscall(SYS_getrandom, buf, buflen, flags);
+    return (int) syscall(SYS_getrandom, buf, buflen, flags);
 }
 #endif /* SYS_getrandom */
 #endif /* __linux__ || __midipix__ */
@@ -112,7 +102,7 @@
 #define HAVE_GETRANDOM
 static int getrandom_wrapper(void *buf, size_t buflen, unsigned int flags)
 {
-    return getrandom(buf, buflen, flags);
+    return (int) getrandom(buf, buflen, flags);
 }
 #endif /* (__FreeBSD__ && __FreeBSD_version >= 1200000) ||
           (__DragonFly__ && __DragonFly_version >= 500700) */
@@ -166,7 +156,7 @@
 #if defined(HAVE_GETRANDOM)
     ret = getrandom_wrapper(output, len, 0);
     if (ret >= 0) {
-        *olen = ret;
+        *olen = (size_t) ret;
         return 0;
     } else if (errno != ENOSYS) {
         return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;