Implement code size count from makefile.

[diagprov]

This commit uses the portable POSIX solution for counting the size of the output library (.a), namely wc -c. The output is specifically produced in the successful "end of make" message. Alternatively, one can now explicitly "make codesize".

We should specifically note that: code size will depend on target architecture (x86_64 has 8-byte pointers, for example) and does not account for the extraction of the various elf-objects. That is, this code currently gives an upper bound estimate of the size INCLUDING ELF metadata and symbols for each and every file in the archive. A release image would strip all this information.