hdf5_msb

Test the format string "ll" before "l", "L", and "q", like the
./configure script does.  This ought to fix the compilation failure
in test/dt_arith.c that Allen told me about:

/home/buildbot/bb-workers/centos8-vm01/hdf5trunk-StdShar-code-centos8/build/hdfsrc/test/dt_arith.c: In function ‘test_conv_int_1’:
/home/buildbot/bb-workers/centos8-vm01/hdf5trunk-StdShar-code-centos8/build/hdfsrc/test/dt_arith.c:2500:34: error: format ‘%ld’ expects argument of type ‘long  int’, but argument 3 has type ‘long long int’ [-Werror=format=]
                 HDfprintf(stdout," %29"H5_PRINTF_LL_WIDTH"d\n", *((long long*)aligned));