tuned signature (again, amending f32ac01aef5e), e.g. relevant for Isabelle/DOF;
#!/usr/bin/env bash
set -e
unset CDPATH
THIS="$(cd "$(dirname "$0")"; pwd)"
cd "$THIS"
source "../../lib/scripts/isabelle-platform"
PLATFORM="${ISABELLE_APPLE_PLATFORM64:-$ISABELLE_PLATFORM64}"
mkdir -p "$PLATFORM"
EXE="$PLATFORM/Isabelle"
gcc -Wall Isabelle.c -o "$EXE"
echo "$EXE"