nauty: disable native code (illegal instructions)

The package currently shipped in void gives me illegal instructions in a
nehalem cpu.

This commit fixes the issue by disabling native compilation unless a build
option is given; also disable popcnt which, although available on nehalem, is
not available in baseline x86_64.

srcpkgs/nauty/template

@@ -1,7 +1,7 @@
 # Template file for 'nauty'
 pkgname=nauty
 version=2.7r3
-revision=1
+revision=2
 wrksrc=${pkgname}${version/./}
 build_style=gnu-configure
 make_install_args="includedir=/usr/include/nauty
@@ -13,6 +13,12 @@ homepage="https://pallini.di.uniroma1.it/"
 distfiles="https://pallini.di.uniroma1.it/nauty${version/./}.tar.gz"
 checksum=4f0665b716a53f7a14ea2ae30059f23d064ce3fe4c12c013404ef6e1ee0b88c2
 
+build_options="native_build"
+
+if [ -z "$build_option_native_build" ]; then
+	configure_args="--enable-generic --disable-popcnt"
+fi
+
 nauty-devel_package() {
 	depends="${sourcepkg}>=${version}_${revision} ${makedepends}"
 	short_desc+=" - development files"