installation problem

I did all the steps from the installation video but still at the end I see these error messages:

symfony/translation suggests installing symfony/config () symfony/translation suggests installing symfony/yaml () symfony/security-core suggests installing symfony/validator (For using the user password constraint) symfony/security-core suggests installing symfony/expression-language (For using the expression voter) symfony/routing suggests installing symfony/config (For using the all-in-one router or any loader) symfony/routing suggests installing symfony/yaml (For using the YAML loader) symfony/routing suggests installing symfony/expression-language (For using expression matching) symfony/routing suggests installing doctrine/annotations (For using the annotation loader) symfony/event-dispatcher suggests installing symfony/dependency-injection () symfony/http-kernel suggests installing symfony/class-loader () symfony/http-kernel suggests installing symfony/config () symfony/http-kernel suggests installing symfony/dependency-injection () predis/predis suggests installing ext-phpiredis (Allows faster serialization and deserialization of the Redis protocol) phpseclib/phpseclib suggests installing ext-mcrypt (Install the Mcrypt extension in order to speed up a wide variety of cryptographic operations.) phpseclib/phpseclib suggests installing ext-gmp (Install the GMP (GNU Multiple Precision) extension in order to speed up arbitrary precision integer arithmetic operations.) phpseclib/phpseclib suggests installing pear-pear/PHP_Compat (Install PHP_Compat to get phpseclib working on PHP < 4.3.3.) patchwork/utf8 suggests installing ext-intl (Use Intl for best performance) patchwork/utf8 suggests installing ext-mbstring (Use Mbstring for best performance) monolog/monolog suggests installing graylog2/gelf-php (Allow sending log messages to a GrayLog2 server) monolog/monolog suggests installing raven/raven (Allow sending log messages to a Sentry server) monolog/monolog suggests installing doctrine/couchdb (Allow sending log messages to a CouchDB server) monolog/monolog suggests installing ruflin/elastica (Allow sending log messages to an Elastic Search server) monolog/monolog suggests installing ext-amqp (Allow sending log messages to an AMQP server (1.0+ required)) monolog/monolog suggests installing ext-mongo (Allow sending log messages to a MongoDB server) monolog/monolog suggests installing aws/aws-sdk-php (Allow sending log messages to AWS services like DynamoDB) monolog/monolog suggests installing rollbar/rollbar (Allow sending log messages to Rollbar) laravel/framework suggests installing doctrine/dbal (Allow renaming columns and dropping SQLite columns.) Writing lock file Generating autoload files Mcrypt PHP extension required. Script php artisan clear-compiled handling the post-install-cmd event returned with an error

I work on a Fedora machine