Remove unused symbol __aarch64

This was added as a possible variant of __aarch64__ back when 64-bit
ARM was vaporware. It hasn't shown up in the wild since then, so remove.

Nathan Bossart

Discussion: https://www.postgresql.org/message-id/CAFBsxsEN5nW3uRh%3Djrs-QexDrC1btu0ZfriD3FFfb%3D3J6tAngg%40mail.gmail.com

src/include/port/atomics.h

@@ -63,8 +63,7 @@
  * compiler barrier.
  *
  */
-#if defined(__arm__) || defined(__arm) || \
-	defined(__aarch64__) || defined(__aarch64)
+#if defined(__arm__) || defined(__arm) || defined(__aarch64__)
 #include "port/atomics/arch-arm.h"
 #elif defined(__i386__) || defined(__i386) || defined(__x86_64__)
 #include "port/atomics/arch-x86.h"

src/include/port/atomics/arch-arm.h

@@ -21,7 +21,7 @@
  * 64 bit atomics on ARM32 are implemented using kernel fallbacks and thus
  * might be slow, so disable entirely. On ARM64 that problem doesn't exist.
  */
-#if !defined(__aarch64__) && !defined(__aarch64)
+#if !defined(__aarch64__)
 #define PG_DISABLE_64_BIT_ATOMICS
 #else
 /*
@@ -29,4 +29,4 @@
  * general purpose register is atomic.
  */
 #define PG_HAVE_8BYTE_SINGLE_COPY_ATOMICITY
-#endif  /* __aarch64__ || __aarch64 */
+#endif  /* __aarch64__ */

src/include/storage/s_lock.h

@@ -256,7 +256,7 @@ spin_delay(void)
  * We use the int-width variant of the builtin because it works on more chips
  * than other widths.
  */
-#if defined(__arm__) || defined(__arm) || defined(__aarch64__) || defined(__aarch64)
+#if defined(__arm__) || defined(__arm) || defined(__aarch64__)
 #ifdef HAVE_GCC__SYNC_INT32_TAS
 #define HAS_TEST_AND_SET
 
@@ -277,7 +277,7 @@ tas(volatile slock_t *lock)
  * high-core-count ARM64 processors.  It seems mostly a wash for smaller gear,
  * and ISB doesn't exist at all on pre-v7 ARM chips.
  */
-#if defined(__aarch64__) || defined(__aarch64)
+#if defined(__aarch64__)
 
 #define SPIN_DELAY() spin_delay()
 
@@ -288,9 +288,9 @@ spin_delay(void)
 		" isb;				\n");
 }
 
-#endif	 /* __aarch64__ || __aarch64 */
+#endif	 /* __aarch64__ */
 #endif	 /* HAVE_GCC__SYNC_INT32_TAS */
-#endif	 /* __arm__ || __arm || __aarch64__ || __aarch64 */
+#endif	 /* __arm__ || __arm || __aarch64__ */
 
 
 /*