The warning message for USE_GNOME, USE_MATE and USE_PHP are as follows:
.if defined(USE_PHP) && (!defined(USES) || ( defined(USES) && !${USES:Mphp*} ))
DEV_WARNING+= "Using USE_PHP alone is deprecated, please use USES=php"
USES+= php
.endif
.if (defined(USE_GNOME) || defined(INSTALLS_ICONS)) && empty(USES:Mgnome)
DEV_WARNING+= "Using USE_GNOME alone is deprecated, please add USES=gnome."
USES+= gnome
.endif
.if defined(USE_MATE) && empty(USES:Mmate)
DEV_WARNING+= "Using USE_MATE alone is deprecated, please add USES=mate."
USES+= mate
.endif