Respect user choice and honor DNT, wrap all the things
First ensure that window.dataLayer is defined to avoid script errors:
window.dataLayer = window.dataLayer || [];
window.dataLayer.push({
//core dataLayer object goes here
});Now wrap the analytics include in the _dntEnabled conditional:
if (!_dntEnabled()) {
(function(w,d,s,l,i,j,f,dl,k,q){
w[l]=w[l]||[];w[l].push({'gtm.start': new Date().getTime(),event:'gtm.js'});f=d.getElementsByTagName(s)[0];
k=i.length;q='//www.googletagmanager.com/gtm.js?id=@&l='+(l||'dataLayer');
while(k--){j=d.createElement(s);j.async=!0;j.src=q.replace('@',i[k]);f.parentNode.insertBefore(j,f);}
}(window,document,'script','dataLayer',['{{settings.GTM_CONTAINER_ID}}']));
}