Start work on version without __COUNTER__
Clean-up: use existing macros
Add preprocessor for compilers without __COUNTER__
Playground: what can preprocessor do
Merge branch 'no-counter'

Add rudimentary support for compilers that do not support the
non-standard __COUNTER__ macro. A special preprocessor was added that
adds the numbering manually.

The build works correctly under Unix and it is possible to compile and
run the tests with both GCC and TinyCC (the latter does not support
__COUNTER__). The build scripts are not fully updated.
Fix typo