build failed on Linux with x32 ABI

[Serguei I. Ivantsov]

Well, please apply the proper patch.
It will also speeds up building on Linux, because rt signals (and
included sysctl.h) are very rare nowadays.

> Yes, that's fine.  But you placed the include added before
> semaphore.h instead of adding it to other event method related
> includes.  I mean to do something like this:
>
> --- a/src/os/unix/ngx_linux_config.h
> +++ b/src/os/unix/ngx_linux_config.h
> @@ -51,7 +51,6 @@
>  #include <malloc.h>             /* memalign() */
>  #include <limits.h>             /* IOV_MAX */
>  #include <sys/ioctl.h>
> -#include <sys/sysctl.h>
>  #include <crypt.h>
>  #include <sys/utsname.h>        /* uname() */
>
> @@ -77,6 +76,11 @@ extern ssize_t sendfile(int s, int fd,
>  #endif
>
>
> +#if (NGX_HAVE_RTSIG)
> +#include <sys/sysctl.h>
> +#endif
> +
> +
>  #if (NGX_HAVE_POLL || NGX_HAVE_RTSIG)
>  #include <poll.h>
>  #endif
>
>
> --
> Maxim Dounin
> http://nginx.org/en/donation.html
>