Tests: sigalgs handling with Net::SSLeay with LibreSSL. LibreSSL does not provide a way to configure signature algorithms, and this makes it impossible to request a particular server certificate when using TLSv1.3. As such, relevant tests fail if Net::SSLeay is compiled with LibreSSL. Notably, this affects macOS, where Net::SSLeay compiled with LibreSSL is shipped with the OS. Fix is to mark relevant tests as TODO if Net:SSLeay is compiled with LibreSSL, similarly to what we already do for sigalg issues in LibreSSL on the server side.

--- a/ssl_certificates.t
+++ b/ssl_certificates.t
@@ -99,8 +99,16 @@ like(cert('RSA'), qr/CN=rsa/, 'ssl cert 
 
 }
 
+TODO: {
+local $TODO = 'no TLSv1.3 sigalgs in Net::SSLeay (LibreSSL)'
+	if Net::SSLeay::constant("LIBRESSL_VERSION_NUMBER")
+	&& !$t->has_module('LibreSSL')
+	&& test_tls13();
+
 like(cert('ECDSA'), qr/CN=ec/, 'ssl cert ECDSA');
 
+}
+
 ###############################################################################
 
 sub test_tls13 {