...

Then create yourself a directory under your home(!) (so it gets backup up) in which you want to create the executable.

For example:

           mkdir -p ~/gem/v_5.1.1/Abs/${My_Abs}

...

It should have close to 50 MB.

4) Modify source code (optional)

a) You can find the main GEM routines under .../gem/src/*/*, for example :

...

            GEM_ovbin=~/gem/v_5.1.1/Abs/${My_Abs}

Modify compiler flags (optional)

Compile one routine without optimization, '-O0'

...