Make start_lexical.sh symbolic-link friendly.

bin/start_lexical.sh

@@ -1,7 +1,16 @@
 #!/usr/bin/env bash
 set -o pipefail
 
-script_dir="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" &>/dev/null && pwd)"
+# find script file, even if we're a link pointing to it
+script_file=${BASH_SOURCE[0]}
+while [ -L "$script_file" ]; do
+    script_dir=$(cd -P "$( dirname "$script_file" )" >/dev/null 2>&1 && pwd)
+    script_file=$(readlink "$script_file")
+    [[ $script_file != /* ]] && script_file=$script_dir/$script_file
+done
+
+# set script_dir to parent dir of script_file
+script_dir=$(cd -P "$( dirname "$script_file" )" >/dev/null 2>&1 && pwd)
 
 # shellcheck disable=SC1091
 if ! . "$script_dir"/activate_version_manager.sh; then