This fixes the following QA warning:
Using USE_GNOME alone is deprecated, please add USES=gnome."
It is currently triggered for:
net/php71-soap net/php71-xmlrpc net/php72-soap net/php72-xmlrpc textproc/php71-dom textproc/php71-simplexml textproc/php71-wddx textproc/php71-xml textproc/php71-xmlreader textproc/php71-xmlwriter textproc/php71-xsl textproc/php72-dom textproc/php72-simplexml textproc/php72-wddx textproc/php72-xml textproc/php72-xmlreader textproc/php72-xmlwriter textproc/php72-xsl
Prevent it in the same way as was done for php73 and php74.
I have added USES=gnome to every other port in the tree. These are the last few.