diff --git a/dlls/mountmgr.sys/Makefile.in b/dlls/mountmgr.sys/Makefile.in
index e1c4bbb1246..36895e3163c 100644
--- a/dlls/mountmgr.sys/Makefile.in
+++ b/dlls/mountmgr.sys/Makefile.in
@@ -2,7 +2,7 @@ MODULE    = mountmgr.sys
 IMPORTS   = uuid advapi32 ntoskrnl.exe
 DELAYIMPORTS = user32
 EXTRADLLFLAGS = -Wb,--subsystem,native
-EXTRADEFS = @DBUS_CFLAGS@ @HAL_CFLAGS@
+EXTRAINCL = @DBUS_CFLAGS@ @HAL_CFLAGS@
 EXTRALIBS = @DISKARBITRATIONLIB@
 
 C_SRCS = \