title: Nginx configure error: can not detect int size
body: <p>when I try to run the "configure" command in nginx src path,the error followed comes out.</p>
  
  <pre><code>checking for OS
  + Linux 2.6.32-71.el6.x86_64 x86_64
  checking for C compiler ... found
  + using GNU C compiler
  + gcc version: 4.4.6 20110731 (Red Hat 4.4.6-3) (GCC) 
  checking for gcc -pipe switch ... found
  checking for gcc builtin atomic operations ... not found
  checking for C99 variadic macros ... not found
  checking for gcc variadic macros ... not found
  checking for unistd.h ... found
  checking for inttypes.h ... found
  checking for limits.h ... found
  checking for sys/filio.h ... not found
  checking for sys/param.h ... found
  checking for sys/mount.h ... found
  checking for sys/statvfs.h ... found
  checking for crypt.h ... found
  checking for Linux specific features
  checking for epoll ... not found
  checking for sendfile() ... not found
  checking for sendfile64() ... not found
  checking for sys/prctl.h ... found
  checking for prctl(PR_SET_DUMPABLE) ... not found
  checking for sched_setaffinity() ... not found
  checking for crypt_r() ... not found
  checking for sys/vfs.h ... found
  checking for poll() ... not found
  checking for /dev/poll ... not found
  checking for kqueue ... not found
  checking for crypt() ... not found
  checking for crypt() in libcrypt ... not found
  checking for F_READAHEAD ... not found
  checking for posix_fadvise() ... not found
  checking for O_DIRECT ... not found
  checking for F_NOCACHE ... not found
  checking for directio() ... not found
  checking for statfs() ... not found
  checking for statvfs() ... not found
  checking for dlopen() ... not found
  checking for dlopen() in libdl ... not found
  checking for sched_yield() ... not found
  checking for sched_yield() in librt ... not found
  checking for SO_SETFIB ... not found
  checking for SO_ACCEPTFILTER ... not found
  checking for TCP_DEFER_ACCEPT ... not found
  checking for TCP_KEEPIDLE, TCP_KEEPINTVL, TCP_KEEPCNT ... not found
  checking for TCP_INFO ... not found
  checking for accept4() ... not found
  checking for int size ...
  ./configure: error: can not detect int size
  </code></pre>
  
  <p>My os is centos 6.0,and it already has the kernel-headers package:
    kernel-headers-2.6.32-71.el6.x86_64
  the os version is:
    CentOS Linux release 6.0 (Final)</p>