coccinelle: drop a couple of FIXMEs

coccinelle: drop a couple of FIXMEs

Turns out Coccinelle can handle compound literals just fine, the parsing
errors were caused by incorrectly parsed macros in code before the
literals, so let's just provide simplified versions for such macros.

The parsing error in `Type *foo[ELEMENTSOF(bar)] = {};` is actually
harmless; it occurs only when creating an array of pointers for a type
that's in an external header and it occurs only on the first parser's
pass, subsequent passes resolve the type correctly.

Also, unset ENABLE_DEBUG_HASHMAP, so Coccinelle doesn't expand the
hashmap debug macros.

As for the remaining FIXMEs, I opened a couple of issues in the
Coccinelle upstream to see if they can be fixed there (or at least
properly analyzed).