t nci sig: bring back nci cstring support

WIP. needed in most external code.
SDL: fix example to use t sig again
SDL: more libSDL_ttf-2.0 choices to search for
[examples] SDL: print SDLLIBPATH= only on failure
nci: broke the nci tests

added cstr converters, and also pshort/pint/plong for PMC access to integers (Integer).