Hello! First, I am sorry if this is already reported but since the gnu website seems to be under constant overload attack and thus is off the web I can't look through the archives.
When trying to compile with a C++ compiler in C++20 or higher mode the C++11 detection script fails to compile due to yupe mismatch. The problem is that the type of u8"x" changed from const char* to const char8_t*. Could this trivial patch please be considered? For copyright assignment reasons I hereby put this patch into the public domain. --- c.m4.orig 2023-12-22 17:17:56.000000000 +0100 +++ c.m4 2025-09-02 18:26:07.432966880 +0200 @@ -2639,7 +2639,7 @@ } { // Unicode literals - char const *utf8 = u8"UTF-8 string \u2500"; + auto const *utf8 = u8"UTF-8 string \u2500"; char16_t const *utf16 = u"UTF-8 string \u2500"; char32_t const *utf32 = U"UTF-32 string \u2500"; } /MF