Instalando ext-mbstring no Fedora Server 23

Se você esta tentando executar o composer.phar se deparou come este erro:

Do not run Composer as root/super user! See https://getcomposer.org/root for details
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - zendframework/zend-math 3.0.x-dev requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - zendframework/zend-math 3.1.x-dev requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - zendframework/zend-math 3.0.0 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - zendframework/zend-math 3.0.0 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - Installation request for zendframework/zend-math ^3.0 -> satisfiable by zendframework/zend-math[3.0.0, 3.1.x-dev, 3.0.x-dev].

  To enable extensions, verify that they are enabled in your .ini files:
    - /etc/php.ini
    - /etc/php.d/20-bz2.ini
    - /etc/php.d/20-calendar.ini
    - /etc/php.d/20-ctype.ini
    - /etc/php.d/20-curl.ini
    - /etc/php.d/20-dom.ini
    - /etc/php.d/20-exif.ini
    - /etc/php.d/20-fileinfo.ini
    - /etc/php.d/20-ftp.ini
    - /etc/php.d/20-gettext.ini
    - /etc/php.d/20-iconv.ini
    - /etc/php.d/20-mysqlnd.ini
    - /etc/php.d/20-pdo.ini
    - /etc/php.d/20-phar.ini
    - /etc/php.d/20-posix.ini
    - /etc/php.d/20-shmop.ini
    - /etc/php.d/20-simplexml.ini
    - /etc/php.d/20-sockets.ini
    - /etc/php.d/20-sqlite3.ini
    - /etc/php.d/20-sysvmsg.ini
    - /etc/php.d/20-sysvsem.ini
    - /etc/php.d/20-sysvshm.ini
    - /etc/php.d/20-tokenizer.ini
    - /etc/php.d/20-xml.ini
    - /etc/php.d/20-xmlwriter.ini
    - /etc/php.d/20-xsl.ini
    - /etc/php.d/30-mysql.ini
    - /etc/php.d/30-mysqli.ini
    - /etc/php.d/30-pdo_mysql.ini
    - /etc/php.d/30-pdo_sqlite.ini
    - /etc/php.d/30-wddx.ini
    - /etc/php.d/30-xmlreader.ini
    - /etc/php.d/40-json.ini
    - /etc/php.d/40-zip.ini
  You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.

Provavelmente esta faltando a extensão ext-mbstring e para instalar basta digitar o comando:

dnf install -y php-mbstring