TYPE_BOOL is defined as a macro in <ConditionalMacros.h>, which gets implicitly included in almost all iOS source files.

This fixes complaints like http://go/soverflow/15759559

For some context, here is how TYPE_BOOL is defined in ConditionalMacros.h

  #ifdef __cplusplus
     #define TYPE_BOOL                1
  #else
     #define TYPE_BOOL                0
  #endif