In the 12.x Release notes, it's noted that the Openmp static lib might be removed in the future releases. it is why that it is removed in this 13.0 release.
It does cause a lot of issues when the app uses MKL libs and also contains code with OpenMP. If the MKL lib is older or the compiler is older, there is imcompatible issue.
The decision on removing it is a cautious one.
Well, we may ask to add the file back, but I'm not sure if it will be. Let's see.
The dynamic Intel OpenMP library may also call upon additional dynamic libraries, to what extent do you want the static libraries (and from whom)?
There was a post on stackoverflow where a person got around this by making self extracting archive (inclusive of the DLLs) and ran the archive as opposed to the included application. That is somewhat of a kludge, but it may work for you.
An alternative might be to package the DLL as a resource, then at program start, copy the resource to a temporary file then use LoadLibrary or LoadLibraryEx to load it. Alternatively there is MemoryModule (https://github.com/fancycode/MemoryModule) that can be used to directly load the DLL from memory.