1) Enforce C99 6.7.3p2: "Types other than pointer types derived from

object or incomplete types shall not be restrict-qualified."

2) Warn about qualifiers on function types: C99 6.7.3p8: "If the 
specification of a function type includes any type qualifiers, the 
behavior is undefined."

3) Implement restrict on C++ references.

4) fix some locations for various C++ reference diagnostics.

llvm-svn: 49081