Transform the Count enum values into private constants

Summary:
Hides implementation details for the C, Objective-C and Swift APIs.
Closes https://github.com/facebook/yoga/pull/292

Differential Revision: D4351523

Pulled By: emilsjolander

fbshipit-source-id: 18a1149d169f0d52bd078714295000b5d07434dd

enums.py

@@ -111,22 +111,22 @@ def to_java_upper(symbol):
     return out
 
 
-root = os.path.dirname(__file__)
+root = os.path.dirname(os.path.abspath(__file__))
 
-# write out C header
+# write out C headers
 with open(root + '/yoga/YGEnums.h', 'w') as f:
     f.write(LICENSE)
     f.write('#pragma once\n\n')
     f.write('#include "YGMacros.h"\n\n')
     f.write('YG_EXTERN_C_BEGIN\n\n')
     for name, values in ENUMS.items():
+        f.write('#define YG%sCount %s\n' % (name, len(values)))
         f.write('typedef enum YG%s {\n' % name)
         for value in values:
             if isinstance(value, tuple):
                 f.write('  YG%s%s = %d,\n' % (name, value[0], value[1]))
             else:
                 f.write('  YG%s%s,\n' % (name, value))
-        f.write('  YG%sCount,\n' % name)
         f.write('} YG%s;\n' % name)
         f.write('\n')
     f.write('YG_EXTERN_C_END\n')