Specify TLS backend

[petemoore]

Since curl 7.58.0 the TLS backend is configurable, and in 7.77.0 it appears to be a mandatory setting. This PR selects the openssl backend.

Note, this may cause problems if the user explicitly specifies an earlier version of curl - but I decided to apply the simple fix rather than testing the version number of curl against 7.58.0. I also didn't provide a means to use a different backend or disable TLS, mostly to keep things simple (and the current script already has hardcoded defaults of --disable-shared and --with-ca-fallback).

This is the failure when building curl 77.7.0 without this fix:

checking curl version... 7.77.0
configure: error: select TLS backend(s) or disable TLS with --without-ssl.

Select from these:

  --with-amissl
  --with-bearssl
  --with-gnutls
  --with-mbedtls
  --with-mesalink
  --with-nss
  --with-openssl (also works for BoringSSL and libressl)
  --with-rustls
  --with-schannel
  --with-secure-transport
  --with-wolfssl

***FAILED! RC=1

I assume openssl is a reasonable backend to use, although I'm no expert.

I added the .gitignore since the script produces the curl* files which shouldn't be checked into the repo.

Thanks!

[God-damnit-all]

Isn't this more or less the same as #6 ?

[petemoore]

Isn't this more or less the same as #6 ?

Oh sorry! I hadn't seen #6 - my bad! Yes, this is just the same, plus the .gitignore. I should have checked for other PRs first...