build: disable -Wstrict-aliasing on darwin

The antiquated gcc/clang that ships with Xcode emits waaaay too many
false positives.

uv.gyp

@@ -115,7 +115,6 @@
             '-pedantic',
             '-Wall',
             '-Wextra',
-            '-Wstrict-aliasing',
             '-Wno-unused-parameter',
           ],
           'sources': [
@@ -181,6 +180,11 @@
             '_DARWIN_USE_64_BIT_INODE=1',
           ]
         }],
+        [ 'OS!="mac"', {
+          # Enable on all platforms except OS X. The antique gcc/clang that
+          # ships with Xcode emits waaaay too many false positives.
+          'cflags': [ '-Wstrict-aliasing' ],
+        }],
         [ 'OS=="linux"', {
           'sources': [
             'src/unix/linux-core.c',
@@ -425,5 +429,3 @@
     }
   ]
 }
-
-