[cppcheck] Remove unused std::ostringstream var
[cppcheck] Remove impossible if branch
[cppcheck] Remove ARX_CAST_TO_INT_THEN_FLOAT()

Was never used.
Simplify condition
[cppcheck] Remove redundant nullptr check
Use original pointer when moving ownership

This makes it clearer that we are transferring ownership of the spell
object and not just passing a temporary pointer to it. Also might
fix a false positive cppcheck warning.
[cppcheck] Fix local variable aliasing
[cppcheck] Remove redundant nullptr check
[cppcheck] Change variable to bool
[cppcheck] Remove unused variable
script: Remove support for unused zoneparam args

The only use of the `zoneparam` script command in 1.21 and the demo is
 ZONE_PARAM AMBIANCE NONE
in marker_0604.
Remove unused ARX_GLOBALMODS_Stack()
Remove unused ARX_GLOBALMODS_UnStack()
Remove unused global variable 'stacked'
[cppcheck] Remove unused LogDirCreation()
[cppcheck] Remove unused MatchPixTex()
[cppcheck] Remove unused WriteIOInfo()
CMake: Use file(GENERATE) to write the 'data' file

… when available.

Fixes warning:
Policy CMP0026 is not set: Disallow use of the LOCATION target property.

See: bug #694
CMake: Use -Wno-uninitialized only when needed
Fully initialize POLYBOOM struct