As hinted in the manual for Lua 5.3, the emulation of the metamethod
for '__le' using '__le' has been deprecated. It is slow, complicates
the logic, and it is easy to avoid this emulation by defining a proper
'__le' function.
Moreover, often this emulation was used wrongly, with a programmer
assuming that an order is total when it is not (e.g., NaN in
floating-point numbers).
These operations also can give errors for lack of resources, so they
also will try "emergency collections" in case of resource errors.
Because there are now two libraries with that kind of handling,
'resourcetryagain' was moved to the auxiliary library to be shared
by the libraries.
Roberto Ierusalimschy