Index: abi/include/_bits/uchar.h
===================================================================
--- abi/include/_bits/uchar.h	(revision 14cbf074bd9a512a47130fc27027a861c38bc286)
+++ abi/include/_bits/uchar.h	(revision 2b5628cc28fe8c72e6fbb3ac05ed0ac55f504d2c)
@@ -38,5 +38,12 @@
 #include <stdint.h>
 
+/*
+ * char8_t became part of C++ with C++20.
+ * It is part of C23 hence we define it for C compilations only.
+ */
+#ifndef __cplusplus
 typedef uint8_t char8_t;
+#endif
+
 typedef uint32_t char32_t;