FYI: KF5Plasma fails to build under MSVC

[Kevin Funk]

See log:

z:\kderoot\download\git\plasma\src\plasma\private/framesvg_helpers.h(47) : 
error C2051: case expression not constant
z:\kderoot\download\git\plasma\src\plasma\private/framesvg_helpers.h(49) : 
error C2051: case expression not constant
z:\kderoot\download\git\plasma\src\plasma\private/framesvg_helpers.h(51) : 
error C2051: case expression not constant
z:\kderoot\download\git\plasma\src\plasma\private/framesvg_helpers.h(53) : 
error C2051: case expression not constant

(more issues of this type (count: 4 more) down in this file)

I could fix this by adding a `EnabledBorder::TopLeft = TopBorder | LeftBorder, 
...` and use this, but this is not the right fix semantically.
Adding another enumaration along `enum foo { TopLeft = 
EnabledBorders::TopBorder | EnabledBorders::LeftBorder, ...}` inside 
framesvg_helpers.h isn't accepted by MSVC either (throws 'expected constant 
expr').

Note: Rest builds fine.

-- 
Kevin Funk | kfunk at kde.org | http://kfunk.org