Most of the warnings were caused by uninitialized values. Some were in plug-ins that didn't have a break in a switch, causing the memory to be deleted twice.
Most of these warnings are due to the use of NULL instead of 0 or NULL instead of '\0'.
Some are macro redefinitions. None of them are pointer storage related. Those will be
in another PR.
Updated compatibility level to 3.19. Set C++17 globally for all platforms. Removed hardcoded compiler and optimisation flags. Adjusted dependencies and libraries linking.
Reworked script building and hog creation.
