polyfill-php55
                                This component provides functions unavailable in releases prior to PHP 5.5.
                            
                        How to download and setup polyfill-php55
Open terminal and run command
                                            git clone https://github.com/symfony/polyfill-php55.git
                                        
                                        git clone is used to create a copy or clone of polyfill-php55 repositories.
                                        You pass git clone a repository URL. it supports a few different network protocols and corresponding URL formats.
Also you may download zip file with polyfill-php55 https://github.com/symfony/polyfill-php55/archive/master.zip
Or simply clone polyfill-php55 with SSH
                                            [email protected]:symfony/polyfill-php55.git                                    
                                    If you have some problems with polyfill-php55
You may open issue on polyfill-php55 support forum (system) here: https://github.com/symfony/polyfill-php55/issuesSimilar to polyfill-php55 repositories
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