diff -up dialog-1.1-20110707/dialog-config.in.incdir dialog-1.1-20110707/dialog-config.in
--- dialog-1.1-20110707/dialog-config.in.incdir	2011-01-06 10:38:03.000000000 +0100
+++ dialog-1.1-20110707/dialog-config.in	2011-07-26 13:00:02.692038027 +0200
@@ -35,6 +35,7 @@ bindir="@bindir@"
 libdir="@libdir@"
 datadir="@datadir@"
 mandir="@mandir@"
+includedir="@includedir@"
 
 THIS="@PACKAGE@"
 
@@ -67,10 +68,7 @@ while test $# -gt 0; do
 		;;
 	# compile/link
 	--cflags)
-		INCS=
-		if test "${prefix}/include" != /usr/include ; then
-			INCS="-I${prefix}/include"
-		fi
+		INCS="-I$includedir"
 		sed -e 's,^[ ]*,,' -e 's, [ ]*, ,g' -e 's,[ ]*$,,' <<-ENDECHO
 			$INCS
 ENDECHO