Fix MSVC version guard for C99 format size specifiers

Visual Studio 2013 (_MSC_VER == 1800) doesn't support %zu - only use it
on 2015 and above (_MSC_VER >= 1900).

%ldd works on Visual Studio 2013, but this patch keeps the two macro
definitions together, for simplicity's sake.

Signed-off-by: Bence Szépkúti <bence.szepkuti@arm.com>

ChangeLog.d/fix-msvc-version-guard-format-zu.txt

+Bugfix
+   * Fix definition of MBEDTLS_PRINTF_SIZET to prevent runtime crashes that
+     occurred whenever SSL debugging was enabled on a copy of Mbed TLS built
+     with Visual Studio 2013.
+     Fixes #10017.

include/mbedtls/debug.h

@@ -108,16 +108,16 @@
  *
  * This module provides debugging functions.
  */
-#if (defined(__MINGW32__) && __USE_MINGW_ANSI_STDIO == 0) || (defined(_MSC_VER) && _MSC_VER < 1800)
+#if (defined(__MINGW32__) && __USE_MINGW_ANSI_STDIO == 0) || (defined(_MSC_VER) && _MSC_VER < 1900)
    #include <inttypes.h>
    #define MBEDTLS_PRINTF_SIZET     PRIuPTR
    #define MBEDTLS_PRINTF_LONGLONG  "I64d"
 #else \
-    /* (defined(__MINGW32__)  && __USE_MINGW_ANSI_STDIO == 0) || (defined(_MSC_VER) && _MSC_VER < 1800) */
+    /* (defined(__MINGW32__)  && __USE_MINGW_ANSI_STDIO == 0) || (defined(_MSC_VER) && _MSC_VER < 1900) */
    #define MBEDTLS_PRINTF_SIZET     "zu"
    #define MBEDTLS_PRINTF_LONGLONG  "lld"
 #endif \
-    /* (defined(__MINGW32__)  && __USE_MINGW_ANSI_STDIO == 0) || (defined(_MSC_VER) && _MSC_VER < 1800) */
+    /* (defined(__MINGW32__)  && __USE_MINGW_ANSI_STDIO == 0) || (defined(_MSC_VER) && _MSC_VER < 1900) */
 
 #if !defined(MBEDTLS_PRINTF_MS_TIME)
 #include <inttypes.h>