From: Tom Honermann <tom@honermann.net>
Date: Sun, 24 Jul 2022 05:11:43 +0000 (-0400)
Subject: stdlib: Suppress gcc diagnostic that char8_t is a keyword in C++20 in uchar.h.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c3fda489cfdb2260f9fec706e6fd7259858c4467;p=thirdparty%2Fglibc.git

stdlib: Suppress gcc diagnostic that char8_t is a keyword in C++20 in uchar.h.

gcc 13 issues the following diagnostic for the uchar.h header when the
-Wc++20-compat option is enabled in C++ modes that do not enable char8_t
as a builtin type (C++17 and earlier by default; subject to _GNU_SOURCE
and the gcc -f[no-]char8_t option).
  warning: identifier ‘char8_t’ is a keyword in C++20 [-Wc++20-compat]
This change modifies the uchar.h header to suppress the diagnostic through
the use of '#pragma GCC diagnostic' directives for gcc 10 and later (the
-Wc++20-compat option was added in gcc version 10).  Unfortunately, a bug
in gcc currently prevents those directives from having the intended effect
as reported at https://gcc.gnu.org/PR106423.  A patch for that issue has
been submitted and is available in the email thread archive linked below.
  https://gcc.gnu.org/pipermail/gcc-patches/2022-July/598736.html

(cherry picked from commit 825f84f133bd840347dc49229b6d831f07d04775)
---

diff --git a/wcsmbs/uchar.h b/wcsmbs/uchar.h
index c37e8619a00..5f7139f2790 100644
--- a/wcsmbs/uchar.h
+++ b/wcsmbs/uchar.h
@@ -34,8 +34,16 @@
 /* Declare the C2x char8_t typedef in C2x modes, but only if the C++
   __cpp_char8_t feature test macro is not defined.  */
 #if __GLIBC_USE (ISOC2X) && !defined __cpp_char8_t
+#if __GNUC_PREREQ (10, 0) && defined __cplusplus
+/* Suppress the diagnostic regarding char8_t being a keyword in C++20.  */
+# pragma GCC diagnostic push
+# pragma GCC diagnostic ignored "-Wc++20-compat"
+#endif
 /* Define the 8-bit character type.  */
 typedef unsigned char char8_t;
+#if __GNUC_PREREQ (10, 0) && defined __cplusplus
+# pragma GCC diagnostic pop
+#endif
 #endif
 
 #ifndef __USE_ISOCXX11