[gcc r13-3618] libstdc++: Remove more redundant union members

[Jonathan Wakely]

https://gcc.gnu.org/g:41602c85ac2414edfbca5c4b0ba520d47f0189ce

commit r13-3618-g41602c85ac2414edfbca5c4b0ba520d47f0189ce
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Nov 2 12:52:34 2022 +0000

    libstdc++: Remove more redundant union members
    
    We don't need these 'unused' members because they're never used, and a
    union with a single variant member is fine.
    
    libstdc++-v3/ChangeLog:
    
            * libsupc++/eh_globals.cc (constant_init::unused): Remove.
            * src/c++11/system_error.cc (constant_init::unused): Remove.
            * src/c++17/memory_resource.cc (constant_init::unused): Remove.

Diff:
---
 libstdc++-v3/libsupc++/eh_globals.cc      | 1 -
 libstdc++-v3/src/c++11/system_error.cc    | 1 -
 libstdc++-v3/src/c++17/memory_resource.cc | 1 -
 3 files changed, 3 deletions(-)

diff --git a/libstdc++-v3/libsupc++/eh_globals.cc b/libstdc++-v3/libsupc++/eh_globals.cc
index 0aadb692a96..12abfc10521 100644
--- a/libstdc++-v3/libsupc++/eh_globals.cc
+++ b/libstdc++-v3/libsupc++/eh_globals.cc
@@ -73,7 +73,6 @@ namespace
   struct constant_init
   {
     union {
-      unsigned char unused;
       __cxa_eh_globals obj;
     };
     constexpr constant_init() : obj() { }
diff --git a/libstdc++-v3/src/c++11/system_error.cc b/libstdc++-v3/src/c++11/system_error.cc
index 8c13642408d..5707e6b61d6 100644
--- a/libstdc++-v3/src/c++11/system_error.cc
+++ b/libstdc++-v3/src/c++11/system_error.cc
@@ -49,7 +49,6 @@ namespace
     struct constant_init
     {
       union {
-	unsigned char unused;
 	T obj;
       };
       constexpr constant_init() : obj() { }
diff --git a/libstdc++-v3/src/c++17/memory_resource.cc b/libstdc++-v3/src/c++17/memory_resource.cc
index 8bc55a69f1f..651d07489aa 100644
--- a/libstdc++-v3/src/c++17/memory_resource.cc
+++ b/libstdc++-v3/src/c++17/memory_resource.cc
@@ -82,7 +82,6 @@ namespace pmr
       struct constant_init
       {
 	union {
-	  unsigned char unused;
 	  T obj;
 	};
 	constexpr constant_init() : obj() { }