CMake >3.2 supports specifying the architecture through the -A parameter,
allowing the logic to be simplified.
Specifying the architecture like this is also required since Visual Studio 2019.
-VSSolution switch now outputs to a dedicated folder if running from source directory.
-Give an error if the user is trying to mix ninja and VSSolution in the same output directory.
-In a MingW environment, give an error on VSSolution switch and give a warning on RTC switch.
-Fix -DNEW_STYLE_BUILD=0 option.
-Ensure the source path doesn't contain any spaces.
-Issue a warning if passed an invalid switch.
-Don't announce completion if there were errors.
-Make end message specific for VSSolution.
-Replace redundant exit commands with quit label, as suggested by HBelusca.
