PHP with OpenSSL

[nicoqh]

After the switch to Ubuntu 16.0.4 we're seeing the following error when making server-side requests:

cURL error 35: gnutls_handshake() failed: An unexpected TLS packet was received.

The majority of requests result in this error, e.g. when attempting to connect to the FCM server.

The previous Debian runtime (runtime: gs://runtime-builders/php-default-builder-20180501142932.yaml) doesn't have this problem.

Curl seems to use GnuTLS/3.4.10, which I suspect is the cause. (The previous runtime uses OpenSSL/1.0.1t.) The issue has been reported elsewhere and prompted Travis to package PHP with OpenSSL instead of GnuTLS.

I'm not sure what the problem is at a deeper level, but we're stuck with the previous Debian runtime for now.

php-docker/package-builder/Dockerfile

Line 59 in da643b9

libcurl4-gnutls-dev \

Any chance we could use libcurl4-openssl-dev?