Cannot seek `mkl-dynamic-*-iomp` when Intel-MKL is not located in `/opt/intel`

[Ionizing]

Hi, I just found intel-mkl-tool may not work well with libiomp5.so when Intel MKL suite is not installed to /opt/intel.

If I didn't misunderstand the code, the function seek_directory just finds the paths of MKL libraries with given root_dir. When Intel MKL suite is installed to /opt/intel, seek_directory just can find the correct path of libiomp5.so since Library::new() already includes /opt/intel, and everything works well. However, libiomp5.so doesn't lie in MKLROOT, but in oneapi/compiler/${version}/${platform}/compiler/lib, leading to the failure.

There might be two possible solution:

• I found intel-mkl-tool used pkg-config to find alternative of MKLROOT, but it may be easier to parse the output of pkg-config --libs mkl-dynamic-lp64-iomp, since the corresponding .pc files are provided by Intel and can work as expected in most environments;
• For the case that pkg-config is not found, just add an additional root_dir=$MKLROOT/../../ and use seek_directory to find the right path. There may be some issues when multiple versions of oneAPI is installed to one root_dir, but this can be resolved by using the same version of MKL and compiler. It seems you've implemented Library::version function but not used it, so here comes the role of it.

I can make an PR to fix this but it would be better to fix it by the author since my coding style may not match this repo very well....