Replace unnecessary instances of strncmp with strcmp. * scripts/optimization/optimget.m, scripts/plot/__gnuplot_drawnow__.m, scripts/plot/fill.m, scripts/plot/private/__go_draw_axes__.m, scripts/plot/private/__pie__.m, scripts/plot/private/__print_parse_opts__.m, scripts/plot/private/__quiver__.m, scripts/plot/private/__tight_eps_bbox__.m, scripts/plot/stairs.m, scripts/plot/uigetfile.m, scripts/strings/strsplit.m, scripts/strings/validatestring.m: Replace unnecessary instances of strncmp with strcmp.

gnulib-hg = gnulib-hg