attributes that are completely internal to Frama-C and do not have any impact
on the semantics of the underlying value should not lead to a cast node.

These tests have missing specs, so the large amount of warnings is expected.

There are still many missing specifications, but at least parsing should
succeed for strictly POSIX-compliant code.

Frama-C does not yet support _Alignof and _Alignas, but this header helps
parsing code and emitting a proper error message.

The ambiguous regex led to behavioral differences under a musl-based libc,
such as in Frama-C's Docker images. The new regex is longer, but avoids the
issue.

- Info (expr_node)
- IndexPI (PlusPI synonym)

Clang 13 emits warnings related to uninitialized variables:

variable 'r' is used uninitialized whenever 'if'
condition is false [-Wsometimes-uninitialized]

This is due to the fact that the assert(0) macro, when using Frama-C's libc,
is expanded to __FC_assert. Since it is not known by the compiler, it cannot
consider it as "noreturn" when the condition is zero. Note that adding
'__attribute__ ((__noreturn__))' will not work: Frama-C will assume it
never returns, even when the condition is true.
Initializing the 'r' variables with a default value will not change the
actual behavior, and will avoid the warnings.