Further improve my fixes to 1984/decot

When I restored the macros it allowed for reinstating the 'union'
instead of 'static struct' and it also allowed for reintroducing the 'x'
(which is '=') in that line so that it looks just like the original:

    union tag u x{4};

For documentation purposes this was added in the thanks file (in the
same part of that entry, the making it look more like the original which
is a worthy goal) as well.

1984/decot/decot.c

@@ -21,7 +21,7 @@ int dup, signal;
 	goto _0;
 
 _O: while (!(k['a'] <<= - dup)) {	/*/*\*/
-	static struct tag u = {4};
+	union tag u x{4};
   }
 }
 

thanks-for-fixes.md

@@ -127,6 +127,10 @@ char x {sizeof(
 
 and changing the type of `k` to be an `int`.
 
+Additionally, because of the `#define union static struct` there is no need to
+have in the code `static struct` as we can have it like the original code which
+has it as `union`.
+
 Originally Yusuke supplied a patch so that this entry would compile with gcc -
 but not clang - or at least some versions.