configure: when enabling QUIC, check that TLS supports QUIC

Most importantly perhaps is when using OpenSSL that the used
build/flavor has the QUIC API: the vanilla OpenSSL does not, only
BoringSSL, libressl, AWS-LC and quictls do.

Ref: 5d044ad948 (r136780413)

Closes #12683

m4/curl-gnutls.m4

@@ -104,6 +104,7 @@ if test "x$OPT_GNUTLS" != xno; then
        GNUTLS_ENABLED=1
        USE_GNUTLS="yes"
        ssl_msg="GnuTLS"
+       QUIC_ENABLED=yes
        test gnutls != "$DEFAULT_SSL_BACKEND" || VALID_DEFAULT_SSL_BACKEND=yes
        ],
        [

m4/curl-openssl.m4

@@ -328,6 +328,15 @@ if test "x$OPT_OPENSSL" != xno; then
     ])
   fi
 
+  dnl is this OpenSSL (fork) providing the original QUIC API?
+  AC_CHECK_FUNCS([SSL_set_quic_use_legacy_codepoint],
+                 [QUIC_ENABLED=yes])
+  if test "$QUIC_ENABLED" = "yes"; then
+    AC_MSG_NOTICE([OpenSSL fork speaks QUIC API])
+  else
+    AC_MSG_NOTICE([OpenSSL version does not speak QUIC API])
+  fi
+
   if test "$OPENSSL_ENABLED" = "1"; then
     if test -n "$LIB_OPENSSL"; then
        dnl when the ssl shared libs were found in a path that the run-time

m4/curl-wolfssl.m4

@@ -107,6 +107,7 @@ if test "x$OPT_WOLFSSL" != xno; then
          WOLFSSL_ENABLED=1
          USE_WOLFSSL="yes"
          ssl_msg="WolfSSL"
+         QUIC_ENABLED=yes
          test wolfssl != "$DEFAULT_SSL_BACKEND" || VALID_DEFAULT_SSL_BACKEND=yes
        ],
        [