Use pkg-config(1) for sndio.

audio/libcanberra/patches/patch-configure_ac

@@ -1,6 +1,7 @@
-$OpenBSD: patch-configure_ac,v 1.11 2012/09/27 06:17:08 ajacoutot Exp $
---- configure.ac.orig	Tue Sep 25 02:21:07 2012
-+++ configure.ac	Thu Sep 27 07:58:59 2012
+$OpenBSD: patch-configure_ac,v 1.12 2022/02/24 12:36:58 ajacoutot Exp $
+Index: configure.ac
+--- configure.ac.orig
++++ configure.ac
 @@ -296,6 +296,36 @@ else
      HAVE_OSS=0
  fi
@@ -23,7 +24,7 @@ $OpenBSD: patch-configure_ac,v 1.11 2012/09/27 06:17:08 ajacoutot Exp $
 +    if test "${ac_cv_header_sndio_h}" = "yes"; then
 +	HAVE_SNDIO=1
 +        AC_DEFINE([HAVE_SNDIO], 1, [Have sndio?])
-+        SNDIO_LIBS='-lsndio'
++        SNDIO_LIBS="$($PKG_CONFIG --libs sndio)"
 +    else
 +	HAVE_SNDIO=0
 +        if test "x$sndio" = xyes ; then