gtk3: Correctly include freetype2 headers

Only <ft2build.h> should be included, all the other header files should be
included via FT_*_H macros.  Should fix PR pkg/53690.

Index: distinfo
===================================================================
RCS file: /cvsroot/pkgsrc/x11/gtk3/distinfo,v
retrieving revision 1.57
diff -u -p -r1.57 distinfo
--- distinfo	23 Oct 2018 07:42:23 -0000	1.57
+++ distinfo	29 Oct 2018 19:53:59 -0000
@@ -12,3 +12,4 @@ SHA1 (patch-gdk_x11_gdkscreen-x11.h) = 4
 SHA1 (patch-gdk_x11_gdkwindow-x11.h) = c80f7c9d5a570817e54fd74fa903a53400dc6f64
 SHA1 (patch-gtk_a11y_gtkaccessibility.c) = 13232c85bd570f21ea03153dacde4ca98c7c76a8
 SHA1 (patch-gtk_fallback-c89.c) = eaf5ac8aace9eab673eed0e265d4cb2617bf1fcd
+SHA1 (patch-gtk_gtkfontchooserwidget.c) = 6ede4fce683b70808c5d611dfb53312bf092665d
Index: patches/patch-gtk_gtkfontchooserwidget.c
===================================================================
RCS file: patches/patch-gtk_gtkfontchooserwidget.c
diff -N patches/patch-gtk_gtkfontchooserwidget.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ patches/patch-gtk_gtkfontchooserwidget.c	29 Oct 2018 19:53:59 -0000
@@ -0,0 +1,19 @@
+$NetBSD$
+
+Correctly include freetype2 headers (<ft2build.h> and then macros
+should be used instead of directly including the headers).
+
+--- gtk/gtkfontchooserwidget.c.orig	2018-07-18 11:04:31.000000000 +0000
++++ gtk/gtkfontchooserwidget.c
+@@ -58,8 +58,9 @@
+ #include <hb.h>
+ #include <hb-ot.h>
+ #include <hb-ft.h>
+-#include <freetype/freetype.h>
+-#include <freetype/ftmm.h>
++#include <ft2build.h>
++#include FT_FREETYPE_H
++#include FT_MULTIPLE_MASTERS_H
+ #include "language-names.h"
+ #include "script-names.h"
+ #endif