Update linux build script

[ksomml]

Fixes issue with building OpenSim GUI on Linux.

Brief summary of changes

Updated the linux build script to the latest changes inside the opensim-core linux build script

Testing I've completed

From my testing the OpenSim GUI 4.4 Release generally does not successfully build with any version of this build script (before and after modifications). Only the main branch seems to properly build the GUI. The only way I managed to install Core+GUI is to set the branch for the core to 4.5.1 and the branch for the gui to main.

CHANGELOG.md (choose one)

• no need to update because I believe generally there should be more work done on improving these build scripts.

Suggestions on further improvements

• open a new repository just for build scripts called opensim-build-scripts (or similar) and link them in opensim-core and opensim-gui. this is very important in my opinion as the way it currently is, you always have two build scripts, making it more difficult to maintain. and weirdly enough the current GUI buildscript always includes the opensim-core installation, so either they should be split or as mentioned in a shared external build script repository
• give the opportunity to decide if core or GUI or both should be installed
• when installing opensim-core it should follow the standard linux install directory instead of installing it into the home directory
• instead of always downloading netbeans and cmake for example, it should check if it already exists and then decide to skip installation or not as for example netbeans will always be downloaded again which takes a long time due to the websites download throttle
• instead of cloning and building the main branch by default (as it is at the moment) it should by default always clone the latest stable release instead, so cases where the main branch of opensim-core in its current state doesn't build on linux (currently its exactly that case) can be avoided.
• i suggest to push the current main branch as a new release version, as the 4.4 OpenSm GUI does not build on Linux

If there would be a new unified and shared repository for the build scripts, i could see myself spending the time to update the build script for linux if help is needed.

[halleysfifthinc]

I'd recommend invoking the opensim install script instead.

[ksomml]

opensim-core was always installed in the GUI script before, I just updated it to the latest changes from the opensim-core linux build script. All latest changes in lines are essentially just copied over.
Or did you mean that specific line marked in your post?

If it would be up to me, I would suggest the improvements mentioned above.

[halleysfifthinc]

Hmmm actually I'm not sure that whole block (lines 223-229) is necessary. The opensim-core build outputs are copied/installed with the OpenSim GUI by default, and the bash script at

opensim-gui/scripts/build/opensim-gui-linux-build-script.sh

Line 251 in 220fe77

bash INSTALL

calls the ./opensim-install-command-line.sh script that installs a link to opensim-cmd in /usr/local/bin. I think as it stands, this build/install script is double installing opensim-core (one copy at the default install prefix, and another copy within the opensim GUI directory).

[ksomml]

That could be the case. I haven't had a look into that INSTALL script yet and won't be able to until Friday. Generally I hope this PR could be used to get some attention on the overdue refactor of the linux build scripts.