[boost] port of test library to vacpp

( Currently the regression status pages for IBM and SGI are not updated for two weeks because I'm unable to even compile the regression test tools. And more and more libraries are braking (on vacpp) so here's another shot at getting them to run again. ) In boost/test/detail/basic_cstring/basic_cstring.hpp contains following line: "enum npos_type { npos = (size_type)-1 }" Now size_type is previously defined as a size_t. The IBM is a 64 bit machine and size_t is 64 bits wide whereas an int is 32 bits wide. Therefore VisualAge does not accept this line. Would soth break if we change this to "enum npos_type { npose = -1 }"