polybarFull: fix build (#513700)

  # Replace hardcoded /etc when copying and reading the default config.

  postPatch = ''

    substituteInPlace CMakeLists.txt --replace "/etc" $out

    substituteInPlace CMakeLists.txt --replace-fail "/etc" $out

    substituteAllInPlace src/utils/file.cpp

    # Fix gcc15 build: i3ipcpp forces -std=c++11 but the jsoncpp library was

    # compiled with C++17 (JSONCPP_HAS_STRING_VIEW=1), causing ABI mismatch.

    # The i3ipcpp code resolves operator[](const char*) but the library only

    # exports operator[](std::string_view). Bump i3ipcpp to C++17 to match.

    substituteInPlace lib/i3ipcpp/CMakeLists.txt --replace-fail \

      "-std=c++11" \

      "-std=c++17"

  '';

  postInstall = ''