Include Fix for GCC11

[LWSS]

Hi, just got GCC11 on my distro, seems that it requires <limits> to be explicitly there.

Original Error is

[blackops@localhost bu]$ make -j12
Scanning dependencies of target RmlCore
[  0%] Building CXX object CMakeFiles/RmlCore.dir/cmake_pch.hxx.gch
In file included from /tmp/RmlUi-master/Include/RmlUi/Config/Config.h:60,
                 from /tmp/RmlUi-master/Include/RmlUi/Core/Types.h:32,
                 from /tmp/RmlUi-master/Include/RmlUi/Core/Core.h:33,
                 from /tmp/RmlUi-master/Include/RmlUi/Core.h:32,
                 from /tmp/RmlUi-master/Source/Core/precompiled.h:32,
                 from /tmp/RmlUi-master/bu/CMakeFiles/RmlCore.dir/cmake_pch.hxx:5,
                 from <command-line>:
/tmp/RmlUi-master/Include/RmlUi/Core/Containers/robin_hood.h: In member function ‘size_t robin_hood::detail::Table<IsFlat, MaxLoadFactor100, Key, T, Hash, KeyEqual>::calcMaxNumElementsAllowed(size_t) const’:
/tmp/RmlUi-master/Include/RmlUi/Core/Containers/robin_hood.h:2021:13: error: ‘numeric_limits’ is not a member of ‘std’
 2021 |         if (ROBIN_HOOD_LIKELY(maxElements <= (std::numeric_limits<size_t>::max)() / 100)) {
      |             ^~~~~~~~~~~~~~~~~
/tmp/RmlUi-master/Include/RmlUi/Core/Containers/robin_hood.h:2021:13: error: expected primary-expression before ‘>’ token
 2021 |         if (ROBIN_HOOD_LIKELY(maxElements <= (std::numeric_limits<size_t>::max)() / 100)) {
      |             ^~~~~~~~~~~~~~~~~
/tmp/RmlUi-master/Include/RmlUi/Core/Containers/robin_hood.h:2021:13: error: ‘::max’ has not been declared; did you mean ‘std::max’?
 2021 |         if (ROBIN_HOOD_LIKELY(maxElements <= (std::numeric_limits<size_t>::max)() / 100)) {
      |             ^~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/11/functional:65,
                 from /tmp/RmlUi-master/Include/RmlUi/Config/Config.h:48,
                 from /tmp/RmlUi-master/Include/RmlUi/Core/Types.h:32,
                 from /tmp/RmlUi-master/Include/RmlUi/Core/Core.h:33,
                 from /tmp/RmlUi-master/Include/RmlUi/Core.h:32,
                 from /tmp/RmlUi-master/Source/Core/precompiled.h:32,
                 from /tmp/RmlUi-master/bu/CMakeFiles/RmlCore.dir/cmake_pch.hxx:5,
                 from <command-line>:
/usr/include/c++/11/bits/stl_algo.h:3467:5: note: ‘std::max’ declared here
 3467 |     max(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
^Cmake[2]: *** Deleting file 'CMakeFiles/RmlCore.dir/cmake_pch.hxx.gch'
make[2]: *** [CMakeFiles/RmlCore.dir/build.make:83: CMakeFiles/RmlCore.dir/cmake_pch.hxx.gch] Interrupt
make[1]: *** [CMakeFiles/Makefile2:124: CMakeFiles/RmlCore.dir/all] Interrupt
make: *** [Makefile:149: all] Interrupt

similar bug here: https://bugs.gentoo.org/753239

[mikke89]

Thanks! This should probably be reported upstream as well: https://github.com/martinus/robin-hood-hashing