GC checks stack space before running finalizer

If the stack does not have some minimum available space, the GC defers
calling a finalizer until the next cycle. That avoids errors while
running a finalizer that the programmer cannot control.

In luaB_close, running coroutines do not go to default

This should had been corrected in commit fd89702.

Warning in loslib.c (signed-unsigned comparison)

Application name for 'readline' is "lua", not "Lua"

New release number, updated copyright year

'lua.h' back to redundancy in version definitions

Several tools inspect 'lua.h' to extract version information, and
they assume the file will have some specific format.

"Emergency" new version 5.4.6

'lua_resetthread' is back to its original signature, to avoid
incompatibilities in the ABI between releases of the same version.
New function 'lua_closethread' added with the "correct" signature.

Details

Typos in comments and details in the manual.

Explanation of borders in the manual

The explanation includes the limit case of maxinteger being a border.
It also avoids the term "natural", which might include large floats
with natural values.

Added option LUA_NOBUILTIN

This option allows external code to avoid the use of gcc builtin macro
'__builtin_expect' in the Lua API.