libstdc++: Fix bootstrap with -fno-rtti [PR 99077]

libstdc++: Fix bootstrap with -fno-rtti [PR 99077]

When libstdc++ is built without RTTI the __ios_failure type is just an
alias for std::ios_failure, so trying to construct it from an int won't
compile. This changes the RTTI-enabled __ios_failure type to have the
same constructor parameters as std::ios_failure, so that the constructor
takes the same arguments whether RTTI is enabled or not.

The __throw_ios_failure function now constructs the error_code, instead
of the __ios_failure constructor. As a drive-by fix that error_code is
constructed with std::generic_category() not std::system_category(),
because the int comes from errno which corresponds to the generic
category.

libstdc++-v3/ChangeLog:

	PR libstdc++/99077
	* src/c++11/cxx11-ios_failure.cc (__ios_failure(const char*, int)):
	Change int parameter to error_code, to match std::ios_failure.
	(__throw_ios_failure(const char*, int)): Construct error_code
	from int parameter.