3853 __cplusplus change and headers incompatipility with clang

*** 24,35 ****
  
  
  #ifndef _MALLOC_H
  #define _MALLOC_H
  
- #pragma ident   "%Z%%M% %I%     %E% SMI"        /* SVr4.0 1.7   */
- 
  #include <sys/types.h>
  
  #ifdef  __cplusplus
  extern "C" {
  #endif
--- 24,33 ----
*** 59,83 ****
          unsigned long keepcost; /* cost of enabling keep option */
  };
  
  #if defined(__STDC__)
  
  void *malloc(size_t);
  void free(void *);
  void *realloc(void *, size_t);
  int mallopt(int, int);
  struct mallinfo mallinfo(void);
- void *calloc(size_t, size_t);
  
  #else
  
  void *malloc();
  void free();
  void *realloc();
  int mallopt();
  struct mallinfo mallinfo();
- void *calloc();
  
  #endif  /* __STDC__ */
  
  #ifdef  __cplusplus
  }
--- 57,98 ----
          unsigned long keepcost; /* cost of enabling keep option */
  };
  
  #if defined(__STDC__)
  
+ #if (!defined(_STRICT_STDC) && !defined(_XOPEN_OR_POSIX)) || \
+         defined(_XPG3)
+ #if __cplusplus >= 199711L
+ namespace std {
+ #endif
+ 
  void *malloc(size_t);
  void free(void *);
  void *realloc(void *, size_t);
+ void *calloc(size_t, size_t);
+ 
+ #if __cplusplus >= 199711L
+ } /* end of namespace std */
+ 
+ using std::malloc;
+ using std::free;
+ using std::realloc;
+ using std::calloc;
+ #endif /* __cplusplus >= 199711L */
+ #endif /* (!defined(_STRICT_STDC) && !defined(_XOPEN_OR_POSIX)) || ... */
+ 
  int mallopt(int, int);
  struct mallinfo mallinfo(void);
  
  #else
  
  void *malloc();
  void free();
  void *realloc();
+ void *calloc();
  int mallopt();
  struct mallinfo mallinfo();
  
  #endif  /* __STDC__ */
  
  #ifdef  __cplusplus
  }