Refactor simd/conf.rb - duplicate code

Integrate duplicate code by extracting headers, types and
initialization code.

Author: nobu

ext/json/ext/simd/conf.rb

@@ -1,29 +1,20 @@
 case RbConfig::CONFIG['host_cpu']
 when /^(arm|aarch64)/
   # Try to compile a small program using NEON instructions
-  if have_header('arm_neon.h') &&
-     try_compile(<<~'SRC')
-      #include <arm_neon.h>
-      int main(int argc, char **argv) {
-          uint8x16_t test = vdupq_n_u8(32);
-          if (argc > 100000) printf("%p", &test);
-          return 0;
-      }
-      SRC
-    $defs.push("-DJSON_ENABLE_SIMD")
-  end
+  header, type, init = 'arm_neon.h', 'uint8x16_t', 'vdupq_n_u8(32)'
 when /^(x86_64|x64)/
-  if have_header('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
+  header, type, init = 'x86intrin.h', '__m128i', '_mm_set1_epi8(32)'
+end
+if header
+  have_header(header) && try_compile(<<~SRC)
+    #{cpp_include(header)}
+    int main(int argc, char **argv) {
+      #{type} test = #{init};
+      if (argc > 100000) printf("%p", &test);
+      return 0;
+    }
+  SRC
+  $defs.push("-DJSON_ENABLE_SIMD")
 end
 
 have_header('cpuid.h')