fix: setting of `MP_UNITS_BUILD_IMPORT_STD` in `generate()` added #113

Job	Run time
std::format none C++20 Clang-18 Release	4m 16s
std::format none C++20 Clang-18 Debug	3m 30s
std::format none C++23 Clang-18 Release	1m 52s
std::format none C++23 Clang-18 Debug	1m 47s
std::format gsl-lite C++20 Clang-18 Release	4m 5s
std::format gsl-lite C++20 Clang-18 Debug	3m 40s
std::format gsl-lite C++23 Clang-18 Release	1m 52s
std::format gsl-lite C++23 Clang-18 Debug	1m 47s
std::format ms-gsl C++20 Clang-18 Release	4m 3s
std::format ms-gsl C++20 Clang-18 Debug	3m 34s
std::format ms-gsl C++23 Clang-18 Release	1m 50s
std::format ms-gsl C++23 Clang-18 Debug	2m 11s
fmtlib none C++20 Clang-18 Release	4m 17s
fmtlib none C++20 Clang-18 Debug	3m 46s
fmtlib none C++23 Clang-18 Release	1m 51s
fmtlib none C++23 Clang-18 Debug	1m 51s
fmtlib gsl-lite C++20 Clang-18 Release	4m 23s
fmtlib gsl-lite C++20 Clang-18 Debug	3m 50s
fmtlib gsl-lite C++23 Clang-18 Release	1m 52s
fmtlib gsl-lite C++23 Clang-18 Debug	1m 54s
fmtlib ms-gsl C++20 Clang-18 Release	4m 9s
fmtlib ms-gsl C++20 Clang-18 Debug	3m 40s
fmtlib ms-gsl C++23 Clang-18 Release	1m 57s
fmtlib ms-gsl C++23 Clang-18 Debug	1m 49s
	1h 9m 46s

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