Basically, something is broken while attempting to install SVN module for PHP via “Modules installer” option. To manually install extension follow these steps:

  1. Download the SVN PECL package: wget

  2. Extract the package: tar xzf svn-1.0.3.tgz

  3. Run phpize for appropriate PHP version: /opt/cpanel/ea-php56/root/usr/bin/phpize

  4. Configure with appropriate PHP configuration: ./configure –with-php-config=/opt/cpanel/ea-php56/root/usr/bin/php-config

  5. Edit the Makefile to add following CFLAGS: CFLAGS = -g -O2 -std=c99

  6. Compile and install extension: make make install

  7. Create configuration for SVN extension: vi /opt/cpanel/ea-php56/root/etc/php.d/svn.ini

and add the following:

    ; Enable svn extension module