Make the lib compile on Ubuntu 25.10+26.04.

[sago007]

Compile fails without C++17. I have tested up to CMake 4.3.2.

I have set booster to not fail on new CMake versions for some time.

I have tested this (using Docker) on Ubuntu 22.04, Ubuntu 26.04, and Debian 13.

I have only touched the gcc path as it is the only one I can reliable test.

It currently fails with errors like:

/usr/include/unicode/char16ptr.h:370:36: note: ‘std::enable_if_t’ is only available from C++14 onwards
/usr/include/unicode/char16ptr.h:370:47: error: expected ‘>’ before ‘<’ token
  370 |           typename = typename std::enable_if_t<std::is_pointer_v<std::remove_reference_t<T>>>,

I found that I needed C++17 to make it compile. It does give some deprecation warnings about std::iterator but it works.

[artyom-beilis]

Which version of gcc? Because it builds without an issue on 22.04?

It seems it is rather related to that ICU requires c++17

/usr/include/unicode/char16ptr.h

Is ICU header

so if you build it with latest ICU that requires C++17 you need to bump the C++ version, if you build without ICU or with different version you don't need it

I think of several options:

1. Check if ICU needs C++17 and than require this flag
2. Check if you can work with C++14 since it is more reasonable requirement
3. Move to C++17 and it opens lots of options in general

Let me think

[sago007]

On ubuntu 25.10 I am running "gcc (Ubuntu 15.2.0-4ubuntu4) 15.2.0" this is where I got the issue and why I had to modify it. It worked fine on Ubuntu 24.04 LTS.

I was considering looking into CMAKE_CXX_STANDARD which sets a maximum C++ version and only uses C++17 if the compiler supports it. However I find CMake quite complicated and went for the minimal approach.

Trying in docker I realize I am unable to replicate the failure on a clean install. I might have to look at it a bit further.

EDIT: I found the issue to be that I had the package "libicu-dev" installed which is version 76.1 and that causes the failure.