CPP12 — Backward compatibility with C

the spec talks about backward compatibility with the C mapping in a number
of places:

• 1.1.14
• at the beginning of 1.7
• in the footnote on page 1-29
• at the end of 1.10
• at the end of 1.12
• at the beginning of 1.13.3
• at the end of 1.16.10
• at the end of 1.20
• at the end of 1.23
• at the beginning of 1.26
• 1.31.3
• 1.42.1

Binary compatibility with the C mapping has never existed and never will.

Proposal: Remove all mention of the C mapping from the above places.

Remove all mention of the C mapping from the above places.