Fix missing int64_t definition #5862

Job	Run time
git_checks	6s
format	26s
macos (macos-13, xcode14_2, x64, shared, serial)	8m 49s
macos (macos-14, xcode15_4, arm64, shared, serial)	8m 50s
ubuntu (ubuntu20.04, gcc8, mpich)	5m 5s
CodeQL (cpp)	18m 59s
ubuntu (ubuntu20.04, gcc9, mpich)	18m 21s
docker (ubuntu-bionic)	7m 7s
macos (macos-14, xcode15_4, arm64, static, serial)	3m 23s
ubuntu (ubuntu20.04, gcc10, mpich)	17m 20s
ubuntu (ubuntu20.04, clang6, mpich)	5m 6s
el8 (el8, icc, mpich)	22m 18s
ubuntu (ubuntu20.04, clang10, mpich)	15m 13s
windows (win2019, shared, msmpi)	19m 10s
el8 (el8, oneapi, mpich)	22m 6s
ubuntu (ubuntu20.04, gcc8, ompi)	34m 40s
windows (win2022, shared, msmpi)	18m 33s
ubuntu (ubuntu20.04, gcc8, serial)	9m 44s
windows (win2022, serial, windows-2022, vs2022)	12m 48s
ubuntu (ubuntu20.04, clang6, ompi)	25m 38s
windows (win2022, static, serial, windows-2022, vs2022)	12m 28s
ubuntu (ubuntu20.04, clang6, serial)	8m 22s
ubuntu (ubuntu20.04, gcc8, serial, static)	9m 21s
ubuntu (ubuntu22.04, rocm, serial, build_only)	3m 6s
ubuntu (ubuntu22.04, gcc11, mpich)	17m 20s
contract (examples)	2m 2s
contract (lammps)	3m 49s
contract (tau)	10m 32s
build_and_test	1s
	5h 40m 43s

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