[BUG] `cp -T` is used by kconfig-merge

### Description / Steps to reproduce the issue

try building esp32s3-devkit:knsh on macOS.
it uses kconfig-merge, which internally uses `cp -T`, which is not available for non-gnu cp.
https://bitbucket.org/nuttx/tools/src/9484147c12d051014f854852d59c21d75a9616bd/kconfig-frontends/utils/kconfig-merge#lines-135

### On which OS does this issue occur?

[OS: Mac]

### What is the version of your OS?

14.7

### NuttX Version

master

### Issue Architecture

[Arch: all]

### Issue Area

[Area: Kconfig]

### Verification

- [X] I have verified before submitting the report.

Start with the referenced kconfig-merge file at the Bitbucket commit, especially line 135 where cp -T is used. Reproduce the esp32s3-devkit:knsh build on macOS 14.7 and inspect how the copy operation can work with non-GNU cp. Done means the build completes on macOS without relying on the unsupported option.

Written by the indexing model from the issue text.