configure: On Apple platforms, only exclude Vulkan on x86.

This catches both x86-64 and ARM devices.
diff --git a/configure b/configure
index cb1423e..f247ccb 100755
--- a/configure
+++ b/configure
@@ -22674,7 +22674,7 @@
                   #include <Metal/Metal.h>
                   #include <QuartzCore/CAMetalLayer.h>
 
-                  #if !TARGET_CPU_X86_64
+                  #if TARGET_CPU_X86
                   #error Vulkan doesn't work on this configuration
                   #endif
 
diff --git a/configure.ac b/configure.ac
index 6018a6d..7481761 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2568,7 +2568,7 @@
                   #include <Metal/Metal.h>
                   #include <QuartzCore/CAMetalLayer.h>
 
-                  #if !TARGET_CPU_X86_64
+                  #if TARGET_CPU_X86
                   #error Vulkan doesn't work on this configuration
                   #endif
                 ],[