--- a/src/process_group.c
+++ b/src/process_group.c
@@ -24,17 +24,10 @@
 #include <limits.h>
 #include <sys/time.h>
 #include <signal.h>
-
-#if defined(__APPLE__) || defined(__FREEBSD__)
-    #include <libgen.h>
-#endif
+#include <libgen.h>
 
 #include <assert.h>
 
-#ifdef __sun__
-    #include <libgen.h>
-#endif
-
 #include "process_iterator.h"
 #include "process_group.h"
 #include "list.h"