mbedtls: make it build even if MBEDTLS_VERSION_C isn't set

Reported-by: MAntoniak on github
Fixes #3553
Closes #3556

diff --git a/lib/vtls/mbedtls.c b/lib/vtls/mbedtls.c
index bb6a757bf2411aca4a1ab6973dce8aefa77b9de2..c36c93e3fa4bcd77013fba3d2cfd1c1e0599711b 100644 (file)
--- a/lib/vtls/mbedtls.c
+++ b/lib/vtls/mbedtls.c
@@ -813,9 +813,14 @@ static void Curl_mbedtls_session_free(void *ptr)
 
 static size_t Curl_mbedtls_version(char *buffer, size_t size)
 {
+#ifdef MBEDTLS_VERSION_C
+  /* if mbedtls_version_get_number() is available it is better */
   unsigned int version = mbedtls_version_get_number();
   return msnprintf(buffer, size, "mbedTLS/%u.%u.%u", version>>24,
                    (version>>16)&0xff, (version>>8)&0xff);
+#else
+  return msnprintf(buffer, size, "mbedTLS/%s", MBEDTLS_VERSION_STRING);
+#endif
 }
 
 static CURLcode Curl_mbedtls_random(struct Curl_easy *data,