opendoas: fix build by disabling HAVE_SYS_TREE_H

The musl implementation of sys/tree.h results in build errors.
Always use the shipped version instead.

srcpkgs/opendoas/template

@@ -1,6 +1,4 @@
 # Template file for 'opendoas'
-broken="Duncaen"
-
 pkgname=opendoas
 version=0.3.1
 revision=1
@@ -26,6 +24,11 @@ pre_configure() {
 		-e '/chown ${BINOWN}:${BINGRP}/d' \
 		-e '/chmod ${BINMODE}/d'
 }
+post_configure() {
+	# Disable -DHAVE_SYS_TREE_H because the
+	# musl implementation results in build errors
+	sed -i config.mk -e 's/.*-DHAVE_SYS_TREE_H/#\0/'
+}
 
 post_install() {
 	vlicense LICENSE