[HawkForge]

Fixes #3489. Thanks to @lwz23 for the report.

For void (__attribute__((noreturn)) *take(int t))(int); libclang spells the function type as void (*(int))(int) __attribute__((noreturn)). FunctionSig::from_ty looks for __attribute__((noreturn)) at parenthesis depth 0 of that spelling, but here the attribute belongs to the pointed-to function type, not to take, so take was emitted as -> !.

When the return type is spelled as a raw function pointer, the function's own attributes follow its parameters inside the (*...) group, e.g. void (*(int) __attribute__((noreturn)))(int) __attribute__((noreturn)) for a function that is noreturn itself. So in that case the check now looks at depth 1 instead of 0. A return type spelled through a typedef (fp (int) __attribute__((noreturn))) and plain functions keep the depth-0 check, and argument attributes (the #2715/#2716 case) stay at depth 2+.

The header test covers take, a noreturn function returning a noreturn function pointer, the typedef'd return with and without noreturn, and a plain noreturn function. Only take changes compared to main; the test fails without the change.

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Replaces #3537, which got closed when my fork was accidentally detached.