[build] Fix build on macOS 10.15 or earlier

Author: lpinca

binding.gyp

@@ -6,11 +6,22 @@
       'cflags': ['-std=c99'],
       'conditions': [
         ["OS=='mac'", {
+          'variables': {
+            'clang_version':
+              '<!(cc -v 2>&1 | perl -ne \'print $1 if /clang version ([0-9]+(\.[0-9]+){2,})/\')'
+          },
           'xcode_settings': {
-            'MACOSX_DEPLOYMENT_TARGET': '10.7',
-            'OTHER_CFLAGS': ['-arch x86_64', '-arch arm64'],
-            'OTHER_LDFLAGS': ['-arch x86_64', '-arch arm64']
-          }
+            'MACOSX_DEPLOYMENT_TARGET': '10.7'
+          },
+          'conditions': [
+            # Use Perl v-strings to compare versions.
+            ['clang_version and <!(perl -e \'print <(clang_version) cmp 12.0.0\')==1', {
+              'xcode_settings': {
+                'OTHER_CFLAGS': ['-arch arm64'],
+                'OTHER_LDFLAGS': ['-arch arm64']
+              }
+            }]
+          ]
         }]
       ]
     }