If a user has Homebrew installed, calling g++ won't use Apple's Xcode version of the tool, which is required by QB64. This fix continues on with the patch introduced in 4dbdddc89e.
Extra "osx" references replaced with "macOS", but nothing substantial (almost aesthetic).
The scroll wheel now behaves correctly on Linux. Reports suggest that the fix does not have any effect
on OSX though. The licensing documentation is updated to reflect the fact that there are no GPL components
included in a QB64 program. Some redundant code was removed from the Windows setup script. OSX setup and
run scripts were missing the executable bit - hopefully the repository will preserve that change.
