Libstdc++: Use IANA name for ISO-8859-1 in format tests.
Libstdc++ format tests now consistently use the IANA name for ISO-8859-1 encoding and require iconv support.
Libstdc++ format tests now consistently use the IANA name for the ISO-8859-1 character encoding (instead of aliases, which may not be universally supported) and ensure that iconv support is available. This change enhances the robustness and portability of the tests. The tests now specify -fexec-charset=ISO-8859-1 and include dg-require-iconv to verify iconv support.
In Details
This commit modifies the testsuite/std/format/debug_nonunicode.cc and testsuite/std/format/fill_nonunicode.cc test files in libstdc++. It ensures that the tests consistently use the IANA name for ISO-8859-1 when specifying the execution character set (-fexec-charset=ISO-8859-1). Additionally, it adds dg-require-iconv to ensure that iconv support is available during testing. This change improves the reliability and portability of the format tests by standardizing the character encoding name and verifying the presence of necessary conversion tools.
For Context
Character encodings are systems for converting text characters into numerical codes that computers can understand. ISO-8859-1 is a common character encoding. This commit updates the libstdc++ test suite to use the standardized IANA name for ISO-8859-1 and checks for iconv which is a standard tool to convert from one encoding to another, that the tests will work correctly regardless of the underlying system's configuration.