code: def scan(node, env, libpath = ()):
      
      try:
          libs = env['LIBS']
      except KeyError:
          # There are no LIBS in this environment, so just return a null list:
          return []
  
      libs = _subst_libs(env, libs)
  
      try:
          prefix = env['LIBPREFIXES']
          if not SCons.Util.is_List(prefix):
              prefix = [ prefix ]
      except KeyError:
          prefix = [ '' ]
  
      try:
          suffix = env['LIBSUFFIXES']
          if not SCons.Util.is_List(suffix):
              suffix = [ suffix ]
      except KeyError:
          suffix = [ '' ]
  
      pairs = []
      for suf in map(env.subst, suffix):
          for pref in map(env.subst, prefix):
              pairs.append((pref, suf))
  
      result = []
  
      if callable(libpath):
          libpath = libpath()
  
      find_file = SCons.Node.FS.find_file
      adjustixes = SCons.Util.adjustixes
      for lib in libs:
          if SCons.Util.is_String(lib):
              for pref, suf in pairs:
                  l = adjustixes(lib, pref, suf)
                  l = find_file(l, libpath, verbose=print_find_libs)
                  if l:
                      result.append(l)
          else:
              result.append(lib)
  
      return result
docs: This scanner scans program files for static-library
      dependencies.  It will search the LIBPATH environment variable
      for libraries specified in the LIBS variable, returning any
      files it finds as dependencies.