Compilation failures cause installation hang

<!--- Verify first that your issue is not already reported on GitHub --> <!--- Also test if the latest release and devel branch are affected too --> <!--- Complete *all* sections as described, this form is processed automatically --> ##### SUMMARY On a Mac without libssh, the installation produces error messages, but never completes. More details at https://github.com/astral-sh/uv/issues/16079 ##### ISSUE TYPE - Bug Report ##### PYLISSH and LIBSSH VERSION <!--- Paste verbatim output between quotes --> ```paste below ``` ##### OS / ENVIRONMENT <!--- Provide all relevant information below, e.g. target OS versions, network device firmware, etc. --> ##### STEPS TO REPRODUCE <!--- Describe exactly how to reproduce the problem, using a minimal test-case --> <!--- Paste example playbooks or commands between quotes below --> ```paste below ``` <!--- HINT: You can paste gist.github.com links for larger files --> ##### EXPECTED RESULTS <!--- Describe what you expected to happen when running the steps above --> ##### ACTUAL RESULTS <!--- Describe what actually happened. If possible run with extra verbosity (-vvvv) --> <!--- Paste verbatim command output between quotes --> ```paste below ```