pkg/51055: devel/pango buildlink3.mk lacks support for libthai option

[kre%munnari.OZ.AU@localhost]

>Number:         51055
>Category:       pkg
>Synopsis:       devel/pango buildlink3.mk lacks support for libthai option
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Apr 09 01:35:00 +0000 2016
>Originator:     Robert Elz
>Release:        NetBSD 7.99.26 (irrelevant) (pkgsrc HEAD as of 2016-04-08)
>Organization:
	Prince of Songkla University
>Environment:
System: NetBSD andromeda.noi.kre.to 7.99.26 NetBSD 7.99.26 (VBOX64-1.1-20160128) #43: Thu Jan 28 16:09:08 ICT 2016 kre%onyx.coe.psu.ac.th@localhost:/usr/obj/current/kernels/amd64/VBOX64 amd64
Architecture: x86_64
Machine: amd64
>Description:
	devel/pango has support for libthai in its build
	(see devel/pango/options.mk) but its buildlink3.mk
	file does not include libthai's - which means that
	packages that include pango (where pango was built
	with the libthai option enabled) fail to find "-lthai"
	(and -ldacrie which is required for libthai, and
	obtained via libthai's buildlink3.mk file).

>How-To-Repeat:
	Build pango with the libthai option enabled (which I
	appreciate is not something many NetBSD developers are
	likely to do ... but which which I actually use), for
	that I have
		PKG_OPTIONS.pango= x11 libthai
	in /etc/mk.conf.

	Then, attempt to build (say) x11/gtk2 - expect link
	failures attempting to reference -lthai and -ldacrie
	(which exist on the build system, but are not included
	in the buildlink environment set up for building gtk2)

>Fix:
	Apply the following patch to devel/pango/buildlink3.mk
	I suspect (hope) this does not require a revbump for pango
	as it affects build time behaviour only (I think that's
	correct...)

Index: buildlink3.mk
===================================================================
RCS file: /cvsroot/NetBSD/pkgsrc/devel/pango/buildlink3.mk,v
retrieving revision 1.44
diff -u -r1.44 buildlink3.mk
--- buildlink3.mk	25 Apr 2015 14:20:38 -0000	1.44
+++ buildlink3.mk	8 Apr 2016 10:36:13 -0000
@@ -19,6 +19,10 @@
 .include "../../x11/libXrender/buildlink3.mk"
 .endif
 
+.if !empty(PKG_BUILD_OPTIONS.pango:Mlibthai)
+.include "../../devel/libthai/buildlink3.mk"
+.endif
+
 .include "../../devel/glib2/buildlink3.mk"
 .include "../../devel/zlib/buildlink3.mk"
 .include "../../fonts/fontconfig/buildlink3.mk"