Add an option to set the option prefix

[ohm314]

in some projects, the ${PROJECT_NAME} variable differs from what we ususally have as the prefix for cmake options. For example:

• CoreNEURON: The cmake ${PROJECT_NAME} is coreneuron but we use CORENRN for all other options.
• NEURON: the project name is NEURON, but we use NRN in many places in the code.

This change allows the programmer to define their own prefix, which can later be used for the variables when building the project.

[matz-e]

This patch increases the complexity of the code maintenance. I understand that this would allow neuron and coreneuron options to be named consistently but can't these projects take the responsibility of their inherent inconsistency instead?

I think that the increase in complexity is actually fairly small (setting the option), and it may allow to truncate very elaborate project names (coreneuron is still kind of small, someone may come up with coreneuron-bglibcpp or so). I'd actually be in favor of this. I would like to be able to grok my command lines and not have to parse ELABORATE_project_NAME_WITH_useless_SUFFIX_COMPILE_OPTIONS all the time

[pramodk]

I also agree with above - for open source projects where it’s difficult to change options/name, this will be very useful. And, as hpc coding convention will serve as common base for many projects, such flexibility might be helpful beyond NEURON/CoreNEURON.