Python 3.1.3 fails to build on HP-UX/PA:
In file included from /opt/build/Python-3.1.3/Modules/_ctypes/libffi/src/dlmalloc.c:1156:
/opt/TWWfsw/gcc42/lib/gcc/hppa2.0-hp-hpux11.31/4.2/include/stdlib.h:577: error: redefinition of 'struct mallinfo'

Failed to build these modules:
_ctypes

<stdlib.h> on HP-UX has a conflicting definition for struct mallinfo:
#ifndef _STRUCT_MALLINFO
#  define _STRUCT_MALLINFO

  /* structure filled by mallinfo */
  struct mallinfo  {
        int32_t arena;          /* total number of bytes in arena */
        int32_t ordblks;        /* number of ordinary blocks */
        int32_t smblks;         /* number of small blocks */
        int32_t hblks;          /* number of holding blocks */
        int32_t hblkhd;         /* number of bytes in holding block headers */
        int32_t usmblks;        /* number of bytes in small blocks in use */
        int32_t fsmblks;        /* number of bytes in free small blocks */
        int32_t uordblks;       /* number of bytes in ordinary blocks in use */
        int32_t fordblks;       /* number of bytes in free ordinary blocks */
        int32_t keepcost;       /* cost of enabling keep option */
  };    
#endif /* _STRUCT_MALLINFO */