The author stated this directly. It is noted in the bugs.md file and the
README.
I also included a suggested change by Yusuke Endoh. This is not
necessary for compilers that support -Wl,-z,execstack but not all
compilers do (though the only one I've found that has this problem is
macOS which it won't work under anyway just like -m32 won't which we
also now use).
Added the 'more portable' version by the author. This does not compile
at least under 64-bit linux (not macOS either though of course it
wouldn't work in macOS as if you look at the code you see hardcoded
paths for linux ld-linux.so).
I note that there's a de-obfuscated version on the author's page for the
entry which might give some clues. I might look at it in the future but
it appears that unless someone can provide a 64-bit linux version this
will be one of the entries (now far fewer with many fixes made) that
simply no longer work.
This thus completes for now 2001/bellard even with disappointing
circumstances.