WGL: Support float-based attrib_list parameters.
WGL: Support float-based attrib_list parameters.

Followup to making it possible in the code generator.

apitrace/apitrace,joshua5201/apitrace,trtt/apitrace,tuanthng/apitrace,swq0553/apitrace,tuanthng/apitrace,surround-io/apitrace,trtt/apitrace,apitrace/apitrace,swq0553/apitrace,schulmar/apitrace,apitrace/apitrace,surround-io/apitrace,schulmar/apitrace,surround-io/apitrace,trtt/apitrace,EoD/apitrace,swq0553/apitrace,tuanthng/apitrace,trtt/apitrace,EoD/apitrace,schulmar/apitrace,swq0553/apitrace,joshua5201/apitrace,schulmar/apitrace,surround-io/apitrace,joshua5201/apitrace,EoD/apitrace,EoD/apitrace,EoD/apitrace,joshua5201/apitrace,schulmar/apitrace,tuanthng/apitrace,joshua5201/apitrace,swq0553/apitrace,apitrace/apitrace,surround-io/apitrace,trtt/apitrace,tuanthng/apitrace