diff --git a/src/ttyname.c b/src/ttyname.c
index fc213d5bc..07ea0fda0 100644
--- a/src/ttyname.c
+++ b/src/ttyname.c
@@ -70,10 +70,10 @@
 # endif
 #endif
 #if defined(HAVE_STRUCT_KINFO_PROC_P_TDEV) || defined (HAVE_STRUCT_KINFO_PROC_KP_EPROC_E_TDEV) || defined(HAVE_STRUCT_KINFO_PROC2_P_TDEV)
-# include <sys/param.h>
+# include <sys/param.h>		/* for makedev/major/minor */
 # include <sys/sysctl.h>
 #elif defined(HAVE_STRUCT_KINFO_PROC_KI_TDEV)
-# include <sys/param.h>
+# include <sys/param.h>		/* for makedev/major/minor */
 # include <sys/sysctl.h>
 # include <sys/user.h>
 #endif
@@ -83,7 +83,7 @@
 # include <sys/procfs.h>
 #endif
 #ifdef HAVE_PSTAT_GETPROC
-# include <sys/param.h>
+# include <sys/param.h>		/* for makedev/major/minor */
 # include <sys/pstat.h>
 #endif