--- mingw-w64-v5.0.2/mingw-w64-tools/widl/Makefile.am.orig	2017-06-19 12:09:10.579443494 +0200
+++ mingw-w64-v5.0.2/mingw-w64-tools/widl/Makefile.am	2017-06-19 12:09:44.896439319 +0200
@@ -58,7 +58,7 @@
   include/pathtools.h \
   include/winnt.rh
 
-widl_CPPFLAGS = -I$(top_srcdir)/include -DDEFAULT_INCLUDE_DIR=\"$(includedir)/../$(target)/include\" -DDEFAULT_BINDIR=\"$(bindir)\"
+widl_CPPFLAGS = -I$(top_srcdir)/include -DDEFAULT_INCLUDE_DIR=\"$(prefix)/$(target)/sys-root/mingw/include\" -DDEFAULT_BINDIR=\"$(bindir)\"
 widl_CFLAGS = -Wall -Wformat -Wpacked -Wmissing-declarations -Wimplicit-function-declaration -Wmissing-prototypes -Wstrict-aliasing=2
 
 DISTCHECK_CONFIGURE_FLAGS = --host=$(host) --target=$(target)
--- mingw-w64-v5.0.2/mingw-w64-tools/widl/Makefile.in.orig	2017-06-19 12:09:18.051442585 +0200
+++ mingw-w64-v5.0.2/mingw-w64-tools/widl/Makefile.in	2017-06-19 12:10:12.177436000 +0200
@@ -285,7 +285,7 @@
   include/pathtools.h \
   include/winnt.rh
 
-widl_CPPFLAGS = -I$(top_srcdir)/include -DDEFAULT_INCLUDE_DIR=\"$(includedir)/../$(target)/include\" -DDEFAULT_BINDIR=\"$(bindir)\"
+widl_CPPFLAGS = -I$(top_srcdir)/include -DDEFAULT_INCLUDE_DIR=\"$(prefix)/$(target)/sys-root/mingw/include\" -DDEFAULT_BINDIR=\"$(bindir)\"
 widl_CFLAGS = -Wall -Wformat -Wpacked -Wmissing-declarations -Wimplicit-function-declaration -Wmissing-prototypes -Wstrict-aliasing=2
 DISTCHECK_CONFIGURE_FLAGS = --host=$(host) --target=$(target)
 all: all-am