cmake: warn for OpenSSL versions missing TLS 1.3 support (revert)

We decided not to show warnings for this issue.

Also this:
```
CMake Warning at CMakeLists.txt:783 (message):
  OpenSSL does not support TLS 1.3.
```
as seen in #16483 with CMake 3.12.4, `OPENSSL_VERSION` is empty.
Perhaps detection isn't reliable? I haven't seen this so far with
mainline OpenSSL. An `if(OPENSSL_VERSION AND ...)` can fix it, if we
opt for this warning in the future.

Follow-up to #16122
This reverts commit 34c1c653fc475efb828658f900979596905c688e #16120
Closes #16485

diff --git a/CMakeLists.txt b/CMakeLists.txt
index be4a1822aee42acc6b829d3d556516e05debd06c..6795b67967061b58b92aee6bbf0b85913c011af4 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -828,9 +828,6 @@ if(CURL_USE_OPENSSL)
     set(_openssl "AmiSSL")
   else()
     set(_openssl "OpenSSL")
-    if(OPENSSL_VERSION VERSION_LESS 1.1.1)
-      message(WARNING "OpenSSL ${OPENSSL_VERSION} does not support TLS 1.3.")
-    endif()
   endif()
 endif()