Quaternion fails to compile with -DCMAKE_DISABLE_PRECOMPILE_HEADERS=YES

[2xsaiko]

Description

Compiling Quaternion with -DCMAKE_DISABLE_PRECOMPILE_HEADERS=YES makes it fail to compile:

In file included from /Users/saiko/Src/tmp/Quaternion/client/networkconfigdialog.cpp:7:
In file included from /Users/saiko/Src/tmp/Quaternion/client/networkconfigdialog.h:9:
In file included from /Users/saiko/Src/tmp/Quaternion/client/dialog.h:9:
In file included from /usr/include/qt6/QtCore/QFlags:1:
In file included from /usr/include/qt6/QtCore/qflags.h:7:
/usr/include/qt6/QtCore/qcompare_impl.h:26:49: error: no member named 'is_null_pointer_v' in namespace 'std'
   26 |     template <typename T, std::enable_if_t<std::is_null_pointer_v<T>, bool> = true>
      |                                            ~~~~~^
/usr/include/qt6/QtCore/qcompare_impl.h:26:67: error: 'T' does not refer to a value
   26 |     template <typename T, std::enable_if_t<std::is_null_pointer_v<T>, bool> = true>
      |                                                                   ^
/usr/include/qt6/QtCore/qcompare_impl.h:26:24: note: declared here
   26 |     template <typename T, std::enable_if_t<std::is_null_pointer_v<T>, bool> = true>
      |                        ^
/usr/include/qt6/QtCore/qcompare_impl.h:26:77: error: expected member name or ';' after declaration specifiers
   26 |     template <typename T, std::enable_if_t<std::is_null_pointer_v<T>, bool> = true>
      |                                                                             ^

I noticed because I was making a Gentoo package for it, and Gentoo's CMake build handler sets this option.

Patch here: 0001-Include-type_traits-to-fix-error-when-compiling-with.patch

Steps to reproduce

• cmake -B build -DCMAKE_DISABLE_PRECOMPILE_HEADERS=YES
• make -C build

Version information

• Quaternion version: 54fc44d1a52ced20adb39023877716abaa399b05, https://github.com/quotient-im/libQuotient/commit/e70e242a9b436532bc57569a76e57330cad53896
• Qt version: 6.7.3
• Install method: Compiled from source
• Platform: Gentoo Linux ~amd64, system compiler is clang, C++ STL is libc++

[KitsuneRal]

Good find, thanks for spotting.