https://issues.dlang.org/show_bug.cgi?id=20659

          Issue ID: 20659
           Summary: C++ header generation does not emit namespaces
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P1
         Component: dmd
          Assignee: nobody@puremagic.com
          Reporter: turkeyman@gmail.com

extern(C++, "namespace") void foo() {}

compile with -HC

When a namespace is specified, the symbol is left out of the header file completely.

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