PHP Attention: PHP Démarrage: Impossible de charger la bibliothèque dynamique '/usr/lib/php/20151012/gd.so'

Ceci est le message d'erreur que je reçois essayer d'installer le MPDF/MPDF.PHP Attention: PHP Démarrage: Impossible de charger la bibliothèque dynamique '/usr/lib/php/20151012/gd.so'

$ composer create-project mpdf/mpdf --prefer-dist 
PHP Warning: PHP Startup: Unable to load dynamic library 
'/usr/lib/php/20151012/gd.so' - /usr/lib/php/20151012/gd.so: cannot open 
shared object file: No such file or directory in Unknown on line 0 
You are running composer with xdebug enabled. This has a major impact on 
runtime performance. See https://getcomposer.org/xdebug

[Composer\Downloader\TransportException]
The " https://packagist.org/packages.json " file could not be downloaded: SSL
operation failed with code 1. OpenSSL Error messages:
error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol
Failed to enable crypto
failed to open stream: operation failed

Je ne sais pas quoi faire pour continuer, pouvez-vous me aider?

Source

2017-10-03 Marcos Henzel