Hello.

After receiving feedback from Richi and Wilco Dijkstra, I decided to fully not
support not null-terminated strings. It brings more complications and the code has started
to be overengineered. Thus c_getstr accepts only such strings and as a bonus it returns
length of a string.

Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.

Ready to be installed?
Martin