feat: add module mp_units

test/unit_test/static/fractional_exponent_quantity.cpp

@@ -20,9 +20,14 @@
 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 // SOFTWARE.
 
+#include <mp-units/quantity_spec_macro.h>
+#ifdef MP_UNITS_MODULES
+import mp_units;
+#else
 #include <mp-units/math.h>
 #include <mp-units/systems/isq/electromagnetism.h>
 #include <mp-units/systems/si/units.h>
+#endif
 
 namespace {