Change vectorlike from struct to union

* src/lisp.h (vectorlike_headed): Change from struct to union.
All uses changed.  Since it has only one member, this does not
change semantics.  This is designed to simplify future changes
needed to fix bugs like Bug#29040.  All uses changed.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/thread.h b/src/thread.h
index 19baafbf8a1..1845974bc28 100644
--- a/src/thread.h
+++ b/src/thread.h
@@ -35,7 +35,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 
 struct thread_state
 {
-  struct vectorlike_header header;
+  union vectorlike_header header;
 
   /* The buffer in which the last search was performed, or
      Qt if the last search was done in a string;
@@ -230,7 +230,7 @@ typedef struct
 /* A mutex as a lisp object.  */
 struct Lisp_Mutex
 {
-  struct vectorlike_header header;
+  union vectorlike_header header;
 
   /* The name of the mutex, or nil.  */
   Lisp_Object name;
@@ -261,7 +261,7 @@ XMUTEX (Lisp_Object a)
 /* A condition variable as a lisp object.  */
 struct Lisp_CondVar
 {
-  struct vectorlike_header header;
+  union vectorlike_header header;
 
   /* The associated mutex.  */
   Lisp_Object mutex;