Improve CCUtil::main_setup (fixes issue #4230)

[stweil]

Conda installations patch TESSDATA_PREFIX in the binary. That does not work for std::string because the length won't be patched, so use a normal C string which can be patched.

Simplify also the code which checks the last character of datadir.

[amitdo]

Conda installations patch TESSDATA_PREFIX in the binary.

What ???

https://docs.conda.io/projects/conda-build/en/stable/resources/make-relocatable.html

That's crazy!

[amitdo]

Do we really want to bend our code just because some distro is doing crazy things?

[stweil]

They really patch all binaries which contain a lengthy magic string (which they configure as prefix). In most cases that allows an installation to a different prefix.

[stweil]

Example: lib/pkgconfig/tesseract.pc is generated with this first line:

prefix=/Users/stweil/src/github/conda-forge/tesseract-feedstock/miniforge3/conda-bld/tesseract_1715530534651/_h_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placeh

The installed file has this first line:

prefix=/opt/homebrew/Caskroom/miniconda/base

[stweil]

Do we really want to bend our code just because some distro is doing crazy things?

I think we would not bend our code in most cases, but in this case our workaround only requires a single code line with an explaining comment. That is less work for us than handling future issue reports if we don't adapt the Tesseract code.

[egorpugin]

In general don't follow it.
We swap to string, to fs::path? Then what?
It's their thing.