libposix: generate compile and runtime versions with configure
* libposix/lib/version.c, libposix/lib/version.h.in: Templates
for code to allow runtime and compile time checking of libposix
version numbers.
* libposix/configure.ac (AC_CONFIG_FILES): Use the already
calculated libposix version number to generate libposix/
lib/version.h.
* libposix/mk-tarball (func_mkver): Removed. Adjust all callers.
Don't generate files required by the build in an optionally
used script, and incidentally avoid recalculating the version
number that configure already knows.