[glibc] hppa: Drop 16-byte pthread lock alignment

[glibc] hppa: Drop 16-byte pthread lock alignment

[John David Anglin]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=ab991a3d1b401ded6bd4f027352da8262b021a11

commit ab991a3d1b401ded6bd4f027352da8262b021a11
Author: John David Anglin <danglin@gcc.gnu.org>
Date:   Sun Mar 26 21:16:22 2023 +0000

    hppa: Drop 16-byte pthread lock alignment
    
    Linux threads were removed about 12 years ago and the current
    nptl implementation only requires 4-byte alignment for pthread
    locks.
    
    The 16-byte alignment causes various issues. For example in
    building ignition-msgs, we have:
    
    /usr/include/google/protobuf/map.h:124:37: error: static assertion failed
      124 |   static_assert(alignof(value_type) <= 8, "");
          |                 ~~~~~~~~~~~~~~~~~~~~^~~~
    
    This is caused by the 16-byte pthread lock alignment.
    
    Signed-off-by: John David Anglin <dave.anglin@bell.net>

Diff:
---
 sysdeps/hppa/nptl/bits/pthreadtypes-arch.h |  2 +-
 sysdeps/hppa/nptl/bits/struct_rwlock.h     | 10 ++++++++--
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/sysdeps/hppa/nptl/bits/pthreadtypes-arch.h b/sysdeps/hppa/nptl/bits/pthreadtypes-arch.h
index 999195c5b0..c1a46d66d0 100644
--- a/sysdeps/hppa/nptl/bits/pthreadtypes-arch.h
+++ b/sysdeps/hppa/nptl/bits/pthreadtypes-arch.h
@@ -40,7 +40,7 @@
 #define __SIZEOF_PTHREAD_RWLOCK_T 64
 #define __SIZEOF_PTHREAD_RWLOCKATTR_T 8
 
-#define __LOCK_ALIGNMENT __attribute__ ((__aligned__(16)))
+#define __LOCK_ALIGNMENT
 #define __ONCE_ALIGNMENT
 
 #endif	/* bits/pthreadtypes.h */
diff --git a/sysdeps/hppa/nptl/bits/struct_rwlock.h b/sysdeps/hppa/nptl/bits/struct_rwlock.h
index e83b4aab52..59bc9fe76f 100644
--- a/sysdeps/hppa/nptl/bits/struct_rwlock.h
+++ b/sysdeps/hppa/nptl/bits/struct_rwlock.h
@@ -25,8 +25,14 @@ struct __pthread_rwlock_arch_t
   /* In the old Linuxthreads pthread_rwlock_t, this is the
      start of the 4-word 16-byte aligned lock structure. The
      next four words are all set to 1 by the Linuxthreads
-     PTHREAD_RWLOCK_INITIALIZER. We ignore them in NPTL.  */
-  int __compat_padding[4] __attribute__ ((__aligned__(16)));
+     PTHREAD_RWLOCK_INITIALIZER. We ignore them in NPTL.
+
+     The 16-byte aligned lock stucture causes various pthread
+     structures to be over aligned. This causes some builds
+     to fail which assume a maximum alignment of 8 bytes.
+     Linuxthreads has been removed for 12 years, so drop
+     alignment of lock structure.  */
+  int __compat_padding[4];
   unsigned int __readers;
   unsigned int __writers;
   unsigned int __wrphase_futex;