wrap cfile's fclose() to avoid warning on latest glibc

[spoonincode]

latest glibc adds a __nonnull attribute on fclose() which ends up causing a bunch of warnings,

libraries/libfc/include/fc/io/cfile.hpp:22:65: warning: ignoring attributes on template argument ‘int (*)(FILE*)’ [-Wignored-attributes]
   22 |    using unique_file = std::unique_ptr<FILE, decltype( &fclose )>;

Not really sure the best way of fixing this. Simply wrapping the call like this gets rid of the warning.

[heifner]

I believe inline would be better here than static.

[spoonincode]

ah yep

[greg7mdp]

Why not just replace the unique_file definition with:
using unique_file = std::unique_ptr<FILE, decltype( [](FILE *f) noexcept { (void)fclose(f); } )>;
and not provide &fclose when constructing a unique_file?

[spoonincode]

Why not just replace the unique_file definition with: using unique_file = std::unique_ptr<FILE, decltype( [](FILE *f) noexcept { (void)fclose(f); } )>; and not provide &fclose when constructing a unique_file?

That caused a different warning for me (that to be honest I didn't investigate)

libraries/libfc/include/fc/io/cfile.hpp:31:7: warning: ‘fc::cfile’ has a field ‘fc::detail::unique_file fc::cfile::_file’ whose type has internal linkage [-Wsubobject-linkage]
   31 | class cfile {

[greg7mdp]

Suggested change

	inline void close_file(FILE* f) {
	inline void close_file(FILE* f) noexcept {