https://docs.phalconphp.com/4.0/en/upgrade#psr

psr *

git clone https://github.com/jbboehr/php-psr.git
cd php-psr 
phpize 
./configure 
make 
make test 
sudo make install

and 

You have to use GCC >= 5.0

install gcc v8.x.x

$ sudo yum install centos-release-scl
$ sudo yum-config-manager --enable rhel-server-rhscl-7-rpms
$ sudo yum install devtoolset-8
$ scl enable devtoolset-8 bash

git clone --depth=1 "git://github.com/phalcon/cphalcon.git"
cd cphalcon/build
sudo ./install