lposix.c: improve comment of mkstemp
lposix.c: improve comment of mkstemp

zevv/luaposix,jimmyharris/luaposix,rrthomas/luaposix,jimmyharris/luaposix,ardje/luaposix,zevv/luaposix,snegovick/luaposix,rrthomas/luaposix,luaposix/luaposix,snegovick/luaposix,ardje/luaposix