Adjust for OpenSSL 1.1.1:

  https://github.com/pyca/pyopenssl/issues/1043

Taken from upstream:

  https://github.com/pyca/pyopenssl/commit/cc5c00ae5fd3c19d07fff79b5c4a08f5e58697ad

diff --git a/src/OpenSSL/SSL.py b/src/OpenSSL/SSL.py
index 59f21cec..fcdee047 100644
--- a/src/OpenSSL/SSL.py
+++ b/src/OpenSSL/SSL.py
@@ -1421,6 +1421,12 @@ def set_alpn_protos(self, protos):
             This list should be a Python list of bytestrings representing the
             protocols to offer, e.g. ``[b'http/1.1', b'spdy/2']``.
         """
+        # Different versions of OpenSSL are inconsistent about how they handle empty
+        # proto lists (see #1043), so we avoid the problem entirely by rejecting them
+        # ourselves.
+        if not protos:
+            raise ValueError("at least one protocol must be specified")
+
         # Take the list of protocols and join them together, prefixing them
         # with their lengths.
         protostr = b"".join(
@@ -2449,6 +2455,12 @@ def set_alpn_protos(self, protos):
             This list should be a Python list of bytestrings representing the
             protocols to offer, e.g. ``[b'http/1.1', b'spdy/2']``.
         """
+        # Different versions of OpenSSL are inconsistent about how they handle empty
+        # proto lists (see #1043), so we avoid the problem entirely by rejecting them
+        # ourselves.
+        if not protos:
+            raise ValueError("at least one protocol must be specified")
+
         # Take the list of protocols and join them together, prefixing them
         # with their lengths.
         protostr = b"".join(
diff --git a/tests/test_ssl.py b/tests/test_ssl.py
index ffc505d8..ca363b45 100644
--- a/tests/test_ssl.py
+++ b/tests/test_ssl.py
@@ -1928,7 +1928,7 @@ def test_alpn_call_failure(self):
         protocols list. Ensure that we produce a user-visible error.
         """
         context = Context(SSLv23_METHOD)
-        with pytest.raises(Error):
+        with pytest.raises(ValueError):
             context.set_alpn_protos([])
 
     def test_alpn_set_on_connection(self):
v class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/bootstrap?id=451730851dde0111a555c1c2da44f05eed5fb383&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-06-13 20:46:01 +0200'>2021-06-13</span></td><td><a href='/guix/commit/bootstrap?id=bd02e50a02ceed914135dba1e69e4457e489cf86'>bootstrap: Simplify search for translation languages.</a><span class='msg-avail'>...<span class='msg-tooltip'>Extend the sed script to also behave like "basename",
saving the addtional call of "xargs basename".

* bootstrap (langs): Extend sed scripts, remove running xargs.
</span></span></td><td>Hartmut Goebel</td></tr>
<tr><td><span title='2020-02-17 11:49:08 +0100'>2020-02-17</span></td><td><a href='/guix/commit/bootstrap?id=3dd311e3a059131ef245417106d4fb659222ef3c'>bootstrap: Fix typo.</a><span class='msg-avail'>...<span class='msg-tooltip'>* bootstrap: Substitute ‘guix-cookbook’ for copy/pasted ‘guix-manual’.

Reported-by: jetomit on #guix
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2019-09-18 11:38:14 +0200'>2019-09-18</span></td><td><a href='/guix/commit/bootstrap?id=7bc46ecc34ceb042ff890e5d306d0a2a736e891d'>doc: Add Guix Cookbook.</a><span class='msg-avail'>...<span class='msg-tooltip'>* .gitignore: Update ignore list.
* Makefile.am (assert-no-store-file-names): Exclude the cookbook.
* bootstrap: Generate po files for cookbook translations.
* doc/guix-cookbook.texi: New file.
* doc/local.mk (info_TEXINFOS): Add it; add a rule to build cookbook
translations.
* po/doc/local.mk (DOC_COOKBOOK_PO_FILES): New variable.
(EXTRA_DIST): Add cookbook pot file and po files.
(doc-po-update-cookbook-%): New target.
(doc-pot-update): Also update cookbook pot file.
(doc-po-update): Also update cookbook po files.
</span></span></td><td>Ricardo Wurmus</td></tr>