algo.h: fix to make it work on Lua 5.1; oops
algo.h: fix to make it work on Lua 5.1; oops

StoneDot/lrexlib,LuaDist/lrexlib-gnu,LuaDist/lrexlib-oniguruma,StoneDot/lrexlib,LuaDist/lrexlib-tre,LuaDist/lrexlib-pcre,LuaDist/lrexlib-posix,LuaDist/lrexlib-gnu,LuaDist/lrexlib-pcre,LuaDist/lrexlib-tre,LuaDist/lrexlib-posix,LuaDist/lrexlib-oniguruma