gnutls relies on glibc-specific getpass functionality in tests

Description of problem:

The certtool test in cert-tests does not detect any password and fails at line 59 since it relies on getpass falling back to stdin and stderr if it is unable to connect to a TTY. This only occurs on glibc (source code), while other libcs like musl (source code) do not have this behaviour.

I can think of a few options to fix this

• Change getpass_copy to directly use utility functions in termios.h. This would be most compatible with existing scripts. Note that according to its man page, getpass is obsolete.
• Stop relying on this behavior and test functionality another way, such as giving another password and making sure certtool fails.
• Try to make a pty so that the existing test line still works. This should be possible, but I have no idea how to do it.

Version of gnutls used:

3.6.12

Distributor of gnutls (e.g., Ubuntu, Fedora, RHEL)

NixOS

How reproducible:

Steps to Reproduce:

• Build gnutls with musl libc (in my case nix-build '<nixpkgs>' -A pkgsMusl.gnutls)
• Run tests

Actual results:

The test fails with the following log:

Generating a 3072 bit RSA private key...
Generating a self signed certificate...
No PIN given.
note: when operating in batch mode, set the GNUTLS_PIN or GNUTLS_SO_PIN environment variables
cert generation failed
FAIL certtool (exit status: 1)

Expected results:

The test should pass