#5650 Use C++11 "override" keyword

[Dan Eble]

1: Remove unnecessary include and namespace use

2: Check name in DECLARE_CLASSNAME()

3: Separate DECLARE_CLASSNAME() from VIRTUAL_COPY_CONSTRUCTOR()

4: Eliminate VIRTUAL_COPY_CONSTRUCTOR()

Just write out the virtual clone() function.

5: Use C++11 "override" keyword throughout the code

The chosen style is to state "virtual" for the base function only, because "override" implies "virtual".

6: Compile with -Werror=suggest-override, when supported

This fails the build if a virtual method is overridden without using the "override" keyword. This complements the standard behavior of failing the build if a virtual method with the "override" keyword does not actually override anything.

https://codereview.appspot.com/551320043

[Anonymous]

Passes make, make check and a full make doc.

[Anonymous]

Patch on countdown for Jan 7th

[Anonymous]

Patch counted down - please push

[Dan Eble]

commit 1ba2d0f8dce97a2dbb3c8f2b6147131ab6f9b10f (origin/staging, staging)
Author: Dan Eble <nine.fierce.ballads@gmail.com>
Date:   Wed Jan 1 14:23:33 2020 -0500

    Issue 5650/6: Compile with -Werror=suggest-override, when supported

    This fails the build if a virtual method is overridden without using the
    "override" keyword.  This complements the standard behavior of failing
    the build if a virtual method with the "override" keyword does not
    actually override anything.

commit 8e6641274af0777a4f93fe6f472eac22d1903d31
Author: Dan Eble <nine.fierce.ballads@gmail.com>
Date:   Wed Jan 1 14:23:33 2020 -0500

    Issue 5650/5: Use C++11 "override" keyword throughout the code

    The chosen style is to state "virtual" for the base function only,
    because "override" implies "virtual".

commit f60b074c15df9f0966a9a4fa2595d75496873f6b
Author: Dan Eble <nine.fierce.ballads@gmail.com>
Date:   Wed Jan 1 12:37:56 2020 -0500

    Issue 5650/4: Eliminate VIRTUAL_COPY_CONSTRUCTOR()

    Just write out the virtual clone() function.

commit 61cb3985a1d8e2055602f36da862c7fea91a9f7c
Author: Dan Eble <nine.fierce.ballads@gmail.com>
Date:   Wed Jan 1 10:51:41 2020 -0500

    Issue 5650/3: Separate DECLARE_CLASSNAME() from VIRTUAL_COPY_CONSTRUCTOR()

commit 11f95a1e576da31913fc470e7bf8f1a87cd0ce11
Author: Dan Eble <nine.fierce.ballads@gmail.com>
Date:   Wed Jan 1 10:49:45 2020 -0500

    Issue 5650/2: Check name in DECLARE_CLASSNAME()

commit bca4b31f8a9a77d0e78af983e9f1ba88fa656dc2
Author: Dan Eble <nine.fierce.ballads@gmail.com>
Date:   Wed Jan 1 09:59:52 2020 -0500

    Issue 5650/1: Remove unnecessary include and namespace use