diff --git a/Makefile.in b/Makefile.in
index c9e4294d..2dbfac24 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -44,7 +44,7 @@ CC=@CC@
 LD=@LD@
 CFLAGS=@CFLAGS@
 CFLAGS_NOPIE=@CFLAGS_NOPIE@
-CPPFLAGS=-I. -I$(srcdir) @CPPFLAGS@ $(PATHS) @DEFS@
+CPPFLAGS=-I. -I$(srcdir) -I$(srcdir)/openbsd-compat @CPPFLAGS@ $(PATHS) @DEFS@
 PICFLAG=@PICFLAG@
 LIBS=@LIBS@
 K5LIBS=@K5LIBS@