x86_64 glibc has started to use it since the 2.43 release.
Link:
https://sourceware.org/git/?p=glibc.git;a=commitdiff;h=b9579342c68b#patch67
---
libstdc++-v3/testsuite/17_intro/badnames.cc | 2 +-
libstdc++-v3/testsuite/17_intro/names.cc | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/libstdc++-v3/testsuite/17_intro/badnames.cc
b/libstdc++-v3/testsuite/17_intro/badnames.cc
index ff590fcdf4d..de4d94faf14 100644
--- a/libstdc++-v3/testsuite/17_intro/badnames.cc
+++ b/libstdc++-v3/testsuite/17_intro/badnames.cc
@@ -67,7 +67,7 @@
// BSD adds:
#define __used __used is a BADNAME
-#define __unused __unused is a BADNAME
+ // __unused (glibc uses this so can't test here)
// __inline (glibc uses this so can't test here)
// _Complex (glibc uses this so can't test here)
#define __istype __istype is a BADNAME
diff --git a/libstdc++-v3/testsuite/17_intro/names.cc
b/libstdc++-v3/testsuite/17_intro/names.cc
index 106acfa641b..2249735baae 100644
--- a/libstdc++-v3/testsuite/17_intro/names.cc
+++ b/libstdc++-v3/testsuite/17_intro/names.cc
@@ -150,7 +150,7 @@
# define __lockable cannot be used as an identifier
# define __null_sentinel cannot be used as an identifier
# define __packed cannot be used as an identifier
-# define __unused cannot be used as an identifier
+ // __unused (glibc uses this so can't test here)
# define __used cannot be used as an identifier
#ifndef __APPLE__
--
2.52.0
