how to install php composer?

[macports at parvis.nl]

without macports, it should be something like this:

curl -sS https://getcomposer.org/installer | php
sudo mv composer.phar /usr/local/bin/composer

but i am afraid that this way interfers with macports.

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then i found the following:  https://github.com/sjorek/MacPorts-PHP

it looks it works like a local port installation.

as this isnt a formal port i think i cannot create a ticket.

this is what happens:

# port install composer composer-php56 composer-select +iconv +openssl
--->  Cleaning composer
--->  Computing dependencies for composer-php56
--->  Building composer-php56
Error: Failed to build composer-php56:
Warning: PHP Startup: Unable to load dynamic library '/opt/local/lib/php56/extensions/no-debug-non-zts-20131226/gd.so' - dlopen(/opt/local/lib/php56/extensions/no-debug-non-zts-20131226/gd.so, 9): image not found in Unknown on line 0

Warning: PHP Startup: Unable to load dynamic library '/opt/local/lib/php56/extensions/no-debug-non-zts-20131226/gdchart.so' - dlopen(/opt/local/lib/php56/extensions/no-debug-non-zts-20131226/gdchart.so, 9): image not found in Unknown on line 0
All settings correct for using Composer
PHP Warning:  PHP Startup: Unable to load dynamic library '/opt/local/lib/php56/extensions/no-debug-non-zts-20131226/gd.so' - dlopen(/opt/local/lib/php56/extensions/no-debug-non-zts-20131226/gd.so, 9): image not found in Unknown on line 0
PHP Warning:  PHP Startup: Unable to load dynamic library '/opt/local/lib/php56/extensions/no-debug-non-zts-20131226/gdchart.so' - dlopen(/opt/local/lib/php56/extensions/no-debug-non-zts-20131226/gdchart.so, 9): image not found in Unknown on line 0
Error: See /opt/local/var/macports/logs/_Users_paul_Develop_macports_MacPorts-PHP_php_composer/composer-php56/main.log for details.
Error: Follow https://guide.macports.org/#project.tickets to report a bug.
Error: Processing of port composer-php56 failed

so it probably isnt the right way too.

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could anybody please tell me the right way to install/use php composer with macports ?

thanks,
pdf.