[boost] [release][1.66.0] Permission to merge Predef.

Some late fixes for Predef came in over the past two days: < https://github.com/boostorg/predef/commit/4a230ebe853980e27e7fb7cb36605fd6cc...

< https://github.com/boostorg/predef/commit/74f88005cc2227b4f8fd4d640daae18c29...

< https://github.com/boostorg/predef/commit/5e8f5d5a4b9df640ffaeaf51e89c83e28a...

Can I merge those to master for the beta? -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net