Address type mismatch warnings on aarch64

[ellert]

The PROVIDER_INFO macro used in the aarch64 code declares all functions with the signature:

extern void function(void);

The actual return type and parameter list of the functions are however different. The declarations provided by the PROVIDER_INFO macro therfore conflicts with the actual declarations of the functions elsewhere in the code, causing compiler warnings.

This commit drops the PROVIDER_INFO macro and provides proper function declarations, eiter by including a header file or by providing a forward declaration. This corresponds to how the code for the other architectures are handlinging this issue.

This PR fixes: #312

[pablodelara]

@liuqinfei could you take a look at this PR? Thanks!

[pablodelara]

@ellert, China is on holidays until next week I think, so @liuqinfei won't be available until then to review.

[liuqinfei]

Hi, ellert. Thanks for your commit.
Macros such as Provider_INFO enable efficient declaration of functions without redundant lines of code.
You can refer to the implementation of x86. When declaring a extern function, you do not need to use the return value type. And here for aarch64, you can see that DIGNOSTIC_IGNORE(-Wnested-externs) has been explicitly used in the macro definition to ignore specific warning messages releated to extern.
And i compiled isal v2.31.1 on the openEuler 22.03 (LTS-SP3) OS with kunpeng920 platform(aarch64). There is no such warning information.
I don't think such a modification is necessary.

[ellert]

There is no such warning information.

Did you try to compile with gcc 15? The problem reported by @pablodelara in #312 and also seen in e.g. this compilation log from the RPM package build on Fedora 42:

https://kojipkgs.fedoraproject.org//packages/isa-l/2.31.1/4.fc42/data/logs/aarch64/build.log

are related to this new compiler version. This is related to that the default C version in this compiler is C23, especially this section of the porting notes is relevant:

https://gcc.gnu.org/gcc-15/porting_to.html#c23-fn-decls-without-parameters

So the error prone behaviour of earlier C versions where a function with an empty parameter list () can take any number of arguments is no longer valid, and an empty parameter list ins now the same as (void), i.e. a function with no arguments.