Update StopWatch.hpp

[daniel-dona]

When installing rdflib-hdt on Ubuntu 24.04 the HDT library build seems to fail with a missing header for the uint64_t datatype.

42.33       x86_64-linux-gnu-g++ -fno-strict-overflow -Wsign-compare -DNDEBUG -g -O2 -Wall -fPIC -I/tmp/pip-build-env-q125cbg6/overlay/local/lib/python3.12/dist-packages/pybind11/include -I/tmp/pip-build-env-q125cbg6/overlay/local/lib/python3.12/dist-packages/pybind11/include -Iinclude/ -Ihdt-cpp-1.3.3/libhdt/include/ -Ihdt-cpp-1.3.3/libhdt/src/dictionary/ -Ihdt-cpp-1.3.3/libhdt/src/sparql/ -Ihdt-cpp-1.3.3/libcds/include/ -Ihdt-cpp-1.3.3/libcds/src/static/bitsequence -Ihdt-cpp-1.3.3/libcds/src/static/coders -Ihdt-cpp-1.3.3/libcds/src/static/mapper -Ihdt-cpp-1.3.3/libcds/src/static/permutation -Ihdt-cpp-1.3.3/libcds/src/static/sequence -Ihdt-cpp-1.3.3/libcds/src/utils -I/usr/include/python3.12 -c hdt-cpp-1.3.3/libhdt/src/util/StopWatch.cpp -o build/temp.linux-x86_64-cpython-312/hdt-cpp-1.3.3/libhdt/src/util/StopWatch.o -std=c++11
42.33       hdt-cpp-1.3.3/libhdt/src/util/StopWatch.cpp: In static member function ‘static std::string StopWatch::toHuman(long long unsigned int)’:
42.33       hdt-cpp-1.3.3/libhdt/src/util/StopWatch.cpp:166:5: error: ‘uint64_t’ was not declared in this scope
42.33         166 |     uint64_t tot_secs = time/1000000;
42.33             |     ^~~~~~~~
42.33       hdt-cpp-1.3.3/libhdt/src/util/StopWatch.cpp:36:1: note: ‘uint64_t’ is defined in header ‘<cstdint>’; did you forget to ‘#include <cstdint>’?
42.33          35 | #include "StopWatch.hpp"
42.33         +++ |+#include <cstdint>
42.33          36 |
42.33       hdt-cpp-1.3.3/libhdt/src/util/StopWatch.cpp:168:30: error: ‘tot_secs’ was not declared in this scope
42.33         168 |         unsigned int hours = tot_secs/3600;
42.33             |                              ^~~~~~~~
42.33       error: command '/usr/bin/x86_64-linux-gnu-g++' failed with exit code 1
42.33       [end of output]
42.33   
42.33   note: This error originates from a subprocess, and is likely not a problem with pip.
42.33   ERROR: Failed building wheel for rdflib-hdt
42.33 Failed to build rdflib-hdt
42.33 ERROR: Could not build wheels for rdflib-hdt, which is required to install pyproject.toml-based projects

This error can be reproduced building the following docker container:

FROM ubuntu:24.04

RUN apt update; apt upgrade -y;
RUN apt install python3 python3-pip -y;

RUN python3 -m pip install rdflib-hdt --break-system-packages

This does not happen on Ubuntu 22.04 that ships with GCC 11, and it seems to be related to changes on GCC 13 (default on Ubuntu 24.04: https://packages.ubuntu.com/noble/gcc ).

From https://gcc.gnu.org/gcc-13/porting_to.html:

Some C++ Standard Library headers have been changed to no longer include other headers that were being used internally by the library. As such, C++ programs that used standard library components without including the right headers will no longer compile.

It could be fixed just including the missing #include <cstdint> header on StopWatch.hpp.