cmake: never use strict aliasing

[illwieckz]

Never use strict aliasing, do the same with nexe than with exe and dll.

Alternative to:

• cmake: only use -fno-strict-aliasing on files requiring it #1159

Instead of trying to always do strict aliasing, never do strict aliasing.

What matters is to have consistent behaviour, #1159 will require more testing than this one.

See:

• Why do we build engine and non-nexe game with -fno-strict-aliasing? #1158

[slipher]

LGTM