libc: only have one select implementation, and move the pollfds onto the heap if they cross some threshold

*** 76,105 ****
  
  /*
   * Select uses bit masks of file descriptors in longs.
   * These macros manipulate such bit fields.
   * FD_SETSIZE may be defined by the user, but the default here
!  * should be >= NOFILE (param.h).
   */
  #ifndef FD_SETSIZE
- #ifdef _LP64
  #define FD_SETSIZE      65536
- #else
- #define FD_SETSIZE      1024
- #endif  /* _LP64 */
- #elif FD_SETSIZE > 1024 && !defined(_LP64)
- #ifdef __PRAGMA_REDEFINE_EXTNAME
- #pragma redefine_extname        select  select_large_fdset
- #if !defined(__XOPEN_OR_POSIX) || defined(_XPG6) || defined(__EXTENSIONS__)
- #pragma redefine_extname        pselect pselect_large_fdset
- #endif
- #else   /* __PRAGMA_REDEFINE_EXTNAME */
- #define select  select_large_fdset
- #if !defined(__XOPEN_OR_POSIX) || defined(_XPG6) || defined(__EXTENSIONS__)
- #define pselect pselect_large_fdset
- #endif
- #endif  /* __PRAGMA_REDEFINE_EXTNAME */
  #endif  /* FD_SETSIZE */
  
  #if !defined(_XPG4_2) || defined(__EXTENSIONS__)
  typedef long    fd_mask;
  #endif
--- 76,89 ----
  
  /*
   * Select uses bit masks of file descriptors in longs.
   * These macros manipulate such bit fields.
   * FD_SETSIZE may be defined by the user, but the default here
!  * should be >= RLIM_FD_MAX.
   */
  #ifndef FD_SETSIZE
  #define FD_SETSIZE      65536
  #endif  /* FD_SETSIZE */
  
  #if !defined(_XPG4_2) || defined(__EXTENSIONS__)
  typedef long    fd_mask;
  #endif