diff --git a/rtl/amicommon/dos.pp b/rtl/amicommon/dos.pp
index ad45100196..44564f3c2b 100644
--- a/rtl/amicommon/dos.pp
+++ b/rtl/amicommon/dos.pp
@@ -64,6 +64,7 @@ implementation
 {$DEFINE FPC_FEXPAND_VOLUMES} (* Full paths begin with drive specification *)
 {$DEFINE FPC_FEXPAND_DRIVESEP_IS_ROOT}
 {$DEFINE FPC_FEXPAND_NO_DEFAULT_PATHS}
+{$DEFINE FPC_FEXPAND_DIRSEP_IS_UPDIR}
 {$I dos.inc}
 
 
diff --git a/rtl/amicommon/sysutils.pp b/rtl/amicommon/sysutils.pp
index 8307f545f1..1c3bc8a989 100644
--- a/rtl/amicommon/sysutils.pp
+++ b/rtl/amicommon/sysutils.pp
@@ -57,6 +57,7 @@ uses
 {$DEFINE FPC_FEXPAND_VOLUMES} (* Full paths begin with drive specification *)
 {$DEFINE FPC_FEXPAND_DRIVESEP_IS_ROOT}
 {$DEFINE FPC_FEXPAND_NO_DEFAULT_PATHS}
+{$DEFINE FPC_FEXPAND_DIRSEP_IS_UPDIR}
 
 { Include platform independent implementation part }
 {$i sysutils.inc}