Andrew Cottrell - 2022-01-17

Changes in the attached patch are:
1) Update to C++17 from C++11 in prep for clang_client in the future
2) Added missing plugins that have unix project files to the unix workspace when compared to windows workspace.
3) Updated CodeBlocks_wx30-unix.cbp to hopefully allow GTK2 or GTK3 builds by changing environment variables instead of changing both environment and other build options.
4) Major rework of the src build scripts for unix to auto detect directories used and if they cannot then display error and exit.
5) Renamed the src unix shell scripts to be easier to find and use (now have format of Unix*.sh)

Please note that the src/Unix_batch_build_all_30.sh file includes comments about speeding up the build process which works and was posted on the forum by killerbot.

These changes are not expected to affect the bootstrap/configure/make build process as this process does not use the project or workspace files or the shell files modified.