Run with parallel runner only when proc_open is not disabled

Author: mvorisek

src/Command/AnalyserRunner.php

@@ -12,6 +12,7 @@
 use function array_filter;
 use function array_values;
 use function count;
+use function function_exists;
 use function is_file;
 
 class AnalyserRunner
@@ -59,6 +60,7 @@ public function runAnalyser(
 if (
 !$debug
 && $allowParallel
+&& function_exists('proc_open')
 && $mainScript !== null
 && $schedule->getNumberOfProcesses() > 0
 ) {