[Bug c++/105297] [12 Regression] new modules 'xtreme' test cases FAILs

["jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105297

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |redi at gcc dot gnu.org

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
If we want a quick work-around, I think:
--- libstdc++-v3/include/std/charconv.jj        2022-04-19 07:20:56.772166410
+0200
+++ libstdc++-v3/include/std/charconv   2022-04-20 16:27:47.971314921 +0200
@@ -407,6 +407,10 @@ namespace __detail
       return true;
     }

+  struct __from_chars_alnum_to_val_table_type {
+    unsigned char __data[1u << __CHAR_BIT__] = {};
+  };
+
   // Construct and return a lookup table that maps 0-9, A-Z and a-z to their
   // corresponding base-36 value and maps all other characters to 127.
   constexpr auto
@@ -420,7 +424,7 @@ namespace __detail
       = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
          'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
          'U', 'V', 'W', 'X', 'Y', 'Z' };
-    struct { unsigned char __data[1u << __CHAR_BIT__] = {}; } __table;
+    struct __from_chars_alnum_to_val_table_type __table;
     for (auto& __entry : __table.__data)
       __entry = 127;
     for (int __i = 0; __i < 10; ++__i)
or so would do it.