xonotic: allow cross-compilation

sources/darkplaces/makefile checks arch with `uname -m`, which gives
host arch, not target one, and then applies some AMD64-exclusive flags
if it's compiled on AMD64, which causes breaks.

srcpkgs/xonotic/template

@@ -1,7 +1,7 @@
 # Template file for 'xonotic'
 pkgname=xonotic
 version=0.8.6
-revision=2
+revision=3
 hostmakedepends="unzip automake libtool"
 makedepends="gmp-devel MesaLib-devel SDL2-devel libcurl-devel alsa-lib-devel
  libmodplug-devel libvorbis-devel libXpm-devel libjpeg-turbo-devel
@@ -13,7 +13,6 @@ license="GPL-2.0-or-later, BSD-3-Clause"
 homepage="http://xonotic.org"
 distfiles="https://dl.xonotic.org/xonotic-${version}-source.zip"
 checksum=8b92ac781cff4ae89c121a23eacd7dec05a2aabedaccc23a19d1a0958b4012a8
-nocross=yes
 
 do_build() {
 	local target
@@ -25,6 +24,8 @@ do_build() {
 	esac
 	echo $make_build_args
 	cd source/darkplaces
+	sed -i makefile \
+		-e "s;DP_MACHINE:=.*;DP_MACHINE:=${XBPS_TARGET_MACHINE/-musl};"
 	# Inject our $CFLAGS and $LDFLAGS
 	sed -i makefile.inc \
 		-e "s;^\(CPUOPTIMIZATIONS\)?=\(.*\);\1=${CFLAGS} \2;" \
@@ -35,7 +36,7 @@ do_build() {
 
 	cd ${wrksrc}/source/d0_blind_id
 	autoreconf -fi
-	./configure --prefix=/usr --disable-rijndael
+	./configure --prefix=/usr --disable-rijndael --host=$(uname -m)
 	make ${makejobs}
 }