Make comparison operator member functions const

...which avoids overload resolution ambiguities in C++20, when a synthesized
candidate of operator == for a reversed-argument rewrite conflicts with the
actual operator ==, due to the asymmetric const-ness of the implicit object
parameter and the RHS parameter.  (As observed with recent Clang 10 trunk with
-std=c++2a:

> vcl/unx/generic/gdi/salgdi.cxx:138:18: error: use of overloaded operator '!=' is ambiguous (with operand types 'SalX11Screen' and 'SalX11Screen')
>     if( nXScreen != m_nXScreen )
>         ~~~~~~~~ ^  ~~~~~~~~~~
> vcl/inc/unx/saltype.h:22:10: note: candidate function
>     bool operator!=(const SalX11Screen &rOther) { return rOther.mnXScreen != mnXScreen; }
>          ^
> vcl/inc/unx/saltype.h:21:10: note: candidate function
>     bool operator==(const SalX11Screen &rOther) { return rOther.mnXScreen == mnXScreen; }
>          ^
> vcl/inc/unx/saltype.h:21:10: note: candidate function (with reversed parameter order)

)

Change-Id: I5dab4fecfbb7badab06ebd0d779527de9672a02a
Reviewed-on: https://gerrit.libreoffice.org/81352
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

0 files changed, 0 insertions, 0 deletions