gprbuild adds a flag -z to the linker commandline
This causes following error during compilation:
/opt/msp430-gcc/bin/../lib/gcc/msp430-elf/8.3.1/../../../../msp430-elf/bin/ld: unrecognized option '-z'
/opt/msp430-gcc/bin/../lib/gcc/msp430-elf/8.3.1/../../../../msp430-elf/bin/ld: use the --help option for usage information
collect2: error: ld returned 1 exit status
The option -R passed to the gprbuild commandline prevents adding
additional parameters.