CMake: Pass `OpenMP` compiler and linker flags through CMake targets

Using `OpenMP::OpenMP_LANG` targets for CMake is less error-prone than
passing the compiler and linker flags manually. Furthermore, it allows
the user to customize those flags by setting `OpenMP_LANG_FLAGS`,
`OpenMP_LANG_LIB_NAMES`, and `OpenMP_omp_LIBRARY`.

Add a trivial GEMMT implementation based on a looped GEMV

Found via `codespell -q 3 -w -L ith,als,dum,nd,amin,nto,wis,ba -S ./relapack,./kernel,./lapack-netlib`

If OpenBLAS is built using add_subdirectory(OpenBlas) as part of another project
then the paths set by CMAKE_XXX_DIR are relative to the parent project
and not the OpenBLAS project.

Disable CBLAS and LAPACK.

Instead of generating separate object files for each permutation of
defines for a source file, GenerateNamedObjects now writes an entirely
new source file and inserts the defines as #define c statements.

This solves a problem I ran into with ar.exe where it was refusing to
link objects that had the same filename despite having different paths.

There are a lot of sources for complex float types that are the same
names as the real sources, except with z prepended.

This will generate obj files for SINGLE/DOUBLE/COMPLEX/DOUBLE COMPLEX.

It sets DBLAS_OBJS directly to save a bunch of list appending in the
CMakeLists.txt files.

The BLAS interface folder should now be generated the correct objects
for the DOUBLE case.

Naming isn't right, though, not seeing cblas_xxxx exports in the
resulting library.

It only does the double precision compile currently.

I realized I didn't finish converting Makefile.system yet, so I made
a note of that.