work around autofree conflicts with StringInterp for paths

use `tool_cmd` correctly

vlib/v/util/diff/diff.v

@@ -41,15 +41,15 @@ pub const available_tool = find_working_diff_tool()
 
 // compare_files returns a string displaying the differences between two files.
 pub fn compare_files(path1 string, path2 string, opts CompareOptions) !string {
+ p1, p2 := os.quoted_path(os.real_path(path1)), os.quoted_path(os.real_path(path2))
  if v := opts.env_overwrite_var {
  env_cmd := os.getenv(v)
  if env_cmd != '' {
  tool, args := env_cmd.split_once(' ') or { env_cmd, opts.args }
  os.find_abs_path_of_executable(tool) or {
  return error('error: failed to find comparison command `${tool}`')
  }
- return run_tool('${tool} ${args} ${os.quoted_path(os.real_path(path1))} ${os.quoted_path(os.real_path(path2))}',
- @LOCATION)
+ return run_tool('${tool} ${args} ${p1} ${p2}', @LOCATION)
  }
  }
  tool := if opts.cmd == .auto {
@@ -65,19 +65,18 @@ pub fn compare_files(path1 string, path2 string, opts CompareOptions) !string {
  os.find_abs_path_of_executable(tool_cmd) or {
  return error('error: failed to find comparison command `${tool_cmd}`')
  }
- p1, p2 := os.quoted_path(os.real_path(path1)), os.quoted_path(os.real_path(path2))
  if opts.args == '' {
  args := if defaults := diff.known_diff_tool_defaults[tool] { defaults } else { '' }
  if tool == .diff {
  // Ensure that the diff command supports the color option.
  // E.g., some BSD installations do not include `diffutils` alongside `diff` by default.
- res := run_tool('${tool} ${args} --color=always ${p1} ${p2}', @LOCATION)
+ res := run_tool('${tool_cmd} ${args} --color=always ${p1} ${p2}', @LOCATION)
  if !res.contains('unrecognized option') {
  return res
  }
  }
  }
- return run_tool('${tool} ${opts.args} ${p1} ${p2}', @LOCATION)
+ return run_tool('${tool_cmd} ${opts.args} ${p1} ${p2}', @LOCATION)
 }
 
 // compare_text returns a string displaying the differences between two strings.