Add a test utest.c for the C interface #97

Job	Run time
windows-latest/gcc-v11/Mode-static/Int32	3m 9s
windows-latest/gcc-v11/Mode-shared/Int32	7m 42s
windows-latest/gcc-v11/Mode-static/Int64	7m 35s
windows-latest/gcc-v11/Mode-shared/Int64	12m 8s
ubuntu-latest/gcc-v11/Mode-static/Int32	21s
ubuntu-latest/gcc-v11/Mode-shared/Int32	21s
ubuntu-latest/gcc-v11/Mode-static/Int64	31s
ubuntu-latest/gcc-v11/Mode-shared/Int64	18s
macos-13/gcc-v11/Mode-static/Int32	1m 8s
macos-13/gcc-v11/Mode-shared/Int32	1m 22s
macos-13/gcc-v11/Mode-static/Int64	1m 14s
macos-13/gcc-v11/Mode-shared/Int64	1m 22s
ubuntu-latest/intel-classic-v2021.10/Mode-static/Int32	2m 15s
ubuntu-latest/intel-classic-v2021.10/Mode-shared/Int32	2m 8s
ubuntu-latest/intel-classic-v2021.10/Mode-static/Int64	2m 8s
ubuntu-latest/intel-classic-v2021.10/Mode-shared/Int64	2m 41s
windows-latest/intel-v2023.2/Mode-static/Int32	2m 30s
windows-latest/intel-v2023.2/Mode-static/Int64	2m 19s
ubuntu-latest/intel-v2023.2/Mode-static/Int32	2m 14s
ubuntu-latest/intel-v2023.2/Mode-shared/Int32	2m 3s
ubuntu-latest/intel-v2023.2/Mode-static/Int64	2m 17s
ubuntu-latest/intel-v2023.2/Mode-shared/Int64	2m 4s
macos-latest/gcc-v13/Mode-static/Int32	36s
macos-latest/gcc-v13/Mode-static/Int64	31s
macos-latest/gcc-v13/Mode-shared/Int32	39s
macos-latest/gcc-v13/Mode-shared/Int64	33s
	1h 2m 9s

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