Add support for pcov code coverage driver

env-example

@@ -97,6 +97,7 @@ WORKSPACE_INSTALL_PHPREDIS=true
 WORKSPACE_INSTALL_WORKSPACE_SSH=false
 WORKSPACE_INSTALL_SUBVERSION=false
 WORKSPACE_INSTALL_XDEBUG=false
+WORKSPACE_INSTALL_PCOV=true
 WORKSPACE_INSTALL_PHPDBG=false
 WORKSPACE_INSTALL_SSH2=false
 WORKSPACE_INSTALL_LDAP=false
@@ -157,6 +158,7 @@ PHP_FPM_INSTALL_IMAGE_OPTIMIZERS=true
 PHP_FPM_INSTALL_PHPREDIS=true
 PHP_FPM_INSTALL_MEMCACHED=false
 PHP_FPM_INSTALL_XDEBUG=false
+PHP_FPM_INSTALL_PCOV=false
 PHP_FPM_INSTALL_XHPROF=false
 PHP_FPM_INSTALL_PHPDBG=false
 PHP_FPM_INSTALL_IMAP=false