Address 2011/richards in bugs.md wrt Apple M1

I've kind of wondered for a while if it's due to Apple's restrictions
against memory protection (in mmap() wrt exec/write/read) and it seems
like that this might be the case either for the Apple silicon chip or
others too (I can only test the M1 chip).

I linked to resources found on Apple's website as well as added a bit of
information I discovered but I think at this time this cannot be
resolved easily or at all because Apple seems to think they know better
than everyone else on certain things and unfortunately they make it very
hard to work round these types of decisions. I will proceed to other
years now, starting with 2013/birken, in the next commits ... unless I
find a typo or something in an earlier year prior to continuing 2013 :-)

bugs.md

@@ -1904,12 +1904,28 @@ tends to result in empty output.
 ## [2011/richards](2011/richards/richards.c) ([README.md](2011/richards/README.md))
 ## STATUS: doesn't work with some platforms - please help us fix
 
-This does not appear to work with macOS, resulting in a segfault. We're not
-sure if this is to do with the Apple silicon chip or not but it seems unlikely.
+This does not appear to work with macOS, resulting in a segfault (and sometimes
+a bus error).
+
+We're not
+sure if this is to do with the Apple silicon chip or not but it seems like it
+_might_ (see Apple resources below) be but it could also be a wider problem with macOS. It appears that
+Apple does not allow certain combinations of memory protections with the arm64
+processor.
+
+[Cody Boone Ferguson](/winners.html#Cody_Boone_Ferguson) tried some of the
+workarounds but at this time he could not get it to work. He offers some earlier
+debugging sessions below as well as a resource from the author as well as some
+resources on Apple's website should anyone wish to take a crack at it. He might
+address it later.
+
+### Debugging
+
 At first glance it appeared to be that it might be the function pointers or the
-fact it is trying to execute code in memory. The function pointers were changed
-a bit but this has not helped solve the problem with macOS. A few things that
-were noticed depending on `asan` sanitisers specified. With `address` in linux:
+fact it is trying to execute code in memory (as noted above). The function
+pointers were changed a bit but this has not helped solve the problem with
+macOS. A few things that were noticed depending on `asan` sanitisers specified.
+With `address` in linux:
 
 
 
@@ -1940,6 +1956,7 @@ x[(u)c]
 
 (at least in my tired head?) is NULL. But why does it work then?
 
+NOTE: `u` is `int`.
 
 Under macOS (with the arm64 chip) we get:
 
@@ -2038,6 +2055,9 @@ o rd(u v)
 
 ```
 
+but this seems to not necessarily be relevant since without it it works in
+linux.
+
 A warning of interest when compiling is:
 
 ```
@@ -2064,11 +2084,32 @@ f *lib2[] = { T, ld, lp, lx, l1 } ;
                              ^~
 ```
 
-but I'm not sure if this is relevant or not: it might be.
+This can be fixed easily enough however but it doesn't appear to matter in this
+case.
 
-Finally the author has more about the entry at
+### Resources
+
+#### More from the author
+
+The author has more about the entry at
 <https://github.com/GregorR/ioccc2011>.
 
+#### Apple resources
+
+[Porting Just-In-Time Compilers to Apple
+Silicon](https://developer.apple.com/documentation/apple-silicon/porting-just-in-time-compilers-to-apple-silicon?language=objc)
+
+[Allow Execution of JIT-compiled Code
+Entitlement](https://developer.apple.com/documentation/bundleresources/entitlements/com_apple_security_cs_allow-jit?language=objc)
+
+Looking at
+<https://github.com/apple/darwin-xnu/blob/5394bb038891708cd4ba748da79b90a33b19f82e/bsd/kern/kern_mman.c>
+Cody noticed a curious thing in the `mprotect()` function: `#if
+CONFIG_DYNAMIC_CODE_SIGNING` and the protection variable has the
+`VM_PROT_TRUSTED` set it might allow overriding the problem but this is
+unconfirmed and it's not known when `CONFIG_DYNAMIC_CODE_SIGNING` would be
+defined.
+
 Do you have a fix? We welcome it!