diff --git a/project.gyp b/project.gyp
index 9c70a9dc..53f95958 100644
--- a/project.gyp
+++ b/project.gyp
@@ -124,6 +124,7 @@
         'cflags': [ '-g' ],
         'ldflags': [ '-g' ],
         'xcode_settings': {
+          'ARCHS': ['x86_64'],
           'OTHER_LDFLAGS': ['-g'],
           'GCC_OPTIMIZATION_LEVEL': '0',
         },
@@ -133,6 +134,7 @@
         'cflags': [ '-g' ],
         'ldflags': [ '-g' ],
         'xcode_settings': {
+          'ARCHS': ['x86_64'],
           'OTHER_LDFLAGS': ['-g'],
           'GCC_OPTIMIZATION_LEVEL': '0',
           'OTHER_CPLUSPLUSFLAGS': ['-fsanitize=address'],
@@ -145,6 +147,9 @@
       'Release': {
         'cflags': [ '-O2', '-fno-strict-aliasing' ],
         'cflags!': [ '-O3', '-fstrict-aliasing' ],
+        'xcode_settings': {
+          'ARCHS': ['x86_64'],
+        },
       },
     },
 
diff --git a/tests.gyp b/tests.gyp
index ed97c3e4..11c7769f 100644
--- a/tests.gyp
+++ b/tests.gyp
@@ -83,6 +83,7 @@
       ],
       'ldflags': ['-g'],
       'xcode_settings': {
+        'ARCHS': ['x86_64'],
         'OTHER_LDFLAGS': ['-g'],
         'OTHER_CPLUSPLUSFLAGS': ['-fsanitize=address'],
         'GCC_OPTIMIZATION_LEVEL': '0',
@@ -104,6 +105,7 @@
       }]
     ],
     'xcode_settings': {
+      'ARCHS': ['x86_64'],
       'CLANG_CXX_LANGUAGE_STANDARD': 'c++14',
       'ALWAYS_SEARCH_USER_PATHS': 'NO',
     }