Details:
- Fixed copy-and-paste bug whereby [scz]gemmtrsm_u_opt_d4x4 kernels
for x86_64/core2 were calling the wrong reference code (l instead
of u).
- Fixed some unused variables in x86_64/core2 dotaxpyv and dotxaxpyf
kernels.
- Minor typecasting fix in testsuite/src/test_libblis.c.
- Makefile updates.