meson: Add warnings and errors when using ICC

meson: Add warnings and errors when using ICC

ICC tries to be helpful by not erroring when it sees something that it
doesn't understand, which is completely the opposite of helpful. Meson
0.49.0 does much better at handling this by really trying to make ICC
error, but there are some things in mesa that still get ignored until
0.49.1

v2: - Fix id check, which is 'intel' not 'icc'

Cc: 18.3 <mesa-stable@lists.freedesktop.org>
Reviewed-by: Eric Engestrom <eric.engestrom@intel.com> (v1)