Add support for running "calltool" on Tor via "make callgraph".

Closes #19307.

scripts/maint/run_calltool.sh

@@ -0,0 +1,29 @@
+#!/bin/sh
+
+# You can find calltool at https://gitweb.torproject.org/user/nickm/calltool.git
+
+set -e
+
+if test "x$CALLTOOL_PATH" != "x"; then
+  PYTHONPATH="${CALLTOOL_PATH}:${PYTHONPATH}"
+  export PYTHONPATH
+fi
+
+mkdir -p callgraph
+
+SUBITEMS="fn_invgraph fn_scc fn_scc_weaklinks module_graph module_invgraph module_scc module_scc_weaklinks"
+
+for calculation in $SUBITEMS; do
+  echo "======== $calculation"
+  python -m calltool $calculation > callgraph/$calculation
+done
+
+echo <<EOF > callgraph/README
+This directory holds output from calltool, as run on Tor.  For more
+information about each of these files, see the NOTES and README files in
+the calltool distribution.
+
+You can find calltool at
+    https://gitweb.torproject.org/user/nickm/calltool.git
+EOF
+