separate run script in environment-setting and M2-binary call:

prurpose: set environment without starting M2 (e.g. to check linked libraries with 'ldd')

possible solution:
file 'M2':

exec /run/media/jakob/TOEXT4/work/home_fc18/Projects/M2-master/M2/BUILD/dan/builds.tmp/fedora32/usr-dist/i686-Linux-Fedora-18/bin/M2.run "$@"

file 'M2.sh'

cd /run/media/jakob/TOEXT4/work/home_fc18/Projects/M2-master/M2/BUILD/dan/builds.tmp/fedora32/usr-dist/i686-Linux-Fedora-18/bin/ 
. M2.sh `pwd`
exec bash

file 'usr-dist/i686-Linux-Fedora-18/bin/M2.run':

#! /bin/sh
# We assume that @ pre_bindir @/.. is ${pre_exec_prefix} (see configure.ac)
. `dirname "$0"`/M2.sh `dirname "$0"`
exec `dirname "$0"`/M2-binary "$@"
# Local Variables:
# compile-command: "make -C $M2BUILDDIR/Macaulay2/bin M2 "
# End:

file 'usr-dist/i686-Linux-Fedora-18/bin/M2.sh':

#! /bin/sh
# We assume that @ pre_bindir @/.. is ${pre_exec_prefix} (see configure.ac)
case "linux-gnu" in
   cygwin) export PATH=$1/../lib/Macaulay2/i686-Linux-Fedora-18/lib:$PATH ;;
  darwin*) # Mac OS X:
           export DYLD_LIBRARY_PATH=$1/../lib/Macaulay2/i686-Linux-Fedora-18/lib:$DYLD_LIBRARY_PATH ;;
        *) export   LD_LIBRARY_PATH=$1/../lib/Macaulay2/i686-Linux-Fedora-18/lib:$LD_LIBRARY_PATH ;;
esac

Start by reading the existing M2 launcher and the proposed M2.sh and M2.run scripts in usr-dist/i686-Linux-Fedora-18/bin. Check how the launcher sets library-path environment variables and how M2.run invokes M2-binary. Done means the environment can be inspected without starting M2 while the normal launcher still starts the binary.