Refactor `mk_install_tactic_cpp()` so that it is usable externally via a new

function ``mk_install_tactic_cpp_internal()`` which is called by a
new ``mk_install_tactic_cpp.py`` script. This will allow other build systems to
generate the ``install_tactic.cpp`` files.

scripts/mk_install_tactic_cpp.py

@@ -0,0 +1,47 @@
+#!/usr/bin/env python
+"""
+Determines the available tactics
+in header files in the list of source directions
+and generates a ``install_tactic.cpp`` file in
+the destination directory that defines a function
+``void install_tactics(tactic_manager& ctx)``.
+"""
+import mk_util
+import argparse
+import logging
+import os
+import sys
+
+def check_dir(path):
+  if not os.path.exists(path):
+    logging.error('"{}" does not exist'.format(path))
+    return 1
+
+  if not os.path.isdir(path):
+    logging.error('"{}" is not a directory'.format(path))
+    return 1
+
+  return 0
+
+
+def main(args):
+  logging.basicConfig(level=logging.INFO)
+  parser = argparse.ArgumentParser(description=__doc__)
+  parser.add_argument("destination_dir", help="destination directory")
+  parser.add_argument("source_dirs", nargs="+",
+                      help="One or more source directories to search")
+  pargs = parser.parse_args(args)
+
+  if check_dir(pargs.destination_dir) != 0:
+    return 1
+
+  for source_dir in pargs.source_dirs:
+    if check_dir(source_dir) != 0:
+      return 1
+
+  mk_util.mk_install_tactic_cpp_internal(pargs.source_dirs, pargs.destination_dir)
+  return 0
+
+if __name__ == '__main__':
+  sys.exit(main(sys.argv[1:]))
+