Note that 2001/bellard only works for i386 linux

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.

2001/bellard/bellard.c

@@ -1,6 +1,8 @@
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
+#include <ctype.h>
+#include <sys/mman.h>
 #define k *(int*)
 #define a if(
 #define c ad()
@@ -8,7 +10,7 @@
 #define p while(
 #define x *(char*)
 #define b ==
-#define V =calloc(1,99999)
+#define V =mmap(NULL, 99999, PROT_EXEC | PROT_WRITE | PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0)
 #define f ()
 #define J return
 #define l ae(