fix warnings emitted by clang
fix Issue 10811 - Order dependent IFTI failure
fix Issue 10804 - regression(2.063=>2.064) problem with Appender or dmd?
fix Issue 10722 - Regression (2.064 git-head): Cannot interpret struct at compile-time
Merge pull request #2477 from 9rnsr/fix10722

[REG2.064a] Issue 10722 - Cannot interpret struct at compile-time
Merge pull request #2473 from 9rnsr/fix10804

[REG2.064a] Issue 10804 - problem with Appender or dmd?
Merge pull request #2472 from 9rnsr/fix10811

Issue 10811 - Order dependent IFTI failure
Merge pull request #2469 from WalterBright/fix-clang-warnings

fix warnings emitted by clang