Refactor simd/conf.rb - balance

Align code for arm and x86_64 in parallel.

Author: nobu

ext/json/ext/simd/conf.rb

@@ -1,4 +1,5 @@
-if RbConfig::CONFIG['host_cpu'] =~ /^(arm.*|aarch64.*)/
+case RbConfig::CONFIG['host_cpu']
+when /^(arm|aarch64)/
   # Try to compile a small program using NEON instructions
   if have_header('arm_neon.h')
     have_type('uint8x16_t', headers=['arm_neon.h']) && try_compile(<<~'SRC')
@@ -8,20 +9,20 @@
           if (argc > 100000) printf("%p", &test);
           return 0;
       }
-    SRC
-      $defs.push("-DJSON_ENABLE_SIMD")
+      SRC
+    $defs.push("-DJSON_ENABLE_SIMD")
   end
-end
-
-if have_header('x86intrin.h') && have_type('__m128i', headers=['x86intrin.h']) && try_compile(<<~'SRC')
-  #include <x86intrin.h>
-  int main(int argc, char **argv) {
-      __m128i test = _mm_set1_epi8(32);
-      if (argc > 100000) printf("%p", &test);
-      return 0;
-  }
-  SRC
+when /^(x86_64|x64)/
+  if have_header('x86intrin.h') && have_type('__m128i', headers=['x86intrin.h']) && try_compile(<<~'SRC')
+      #include <x86intrin.h>
+      int main(int argc, char **argv) {
+          __m128i test = _mm_set1_epi8(32);
+          if (argc > 100000) printf("%p", &test);
+          return 0;
+      }
+      SRC
     $defs.push("-DJSON_ENABLE_SIMD")
+  end
 end
 
 have_header('cpuid.h')