Fixed build on Linux with x32 ABI. On Linux x32 inclusion of sys/sysctl.h produces an error. As sysctl() is only used by rtsig event method code, which is legacy and not compiled in by default on modern linuxes, the sys/sysctl.h file now only included if rtsig support is enabled. Based on patch by Serguei I. Ivantsov.

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


have=NGX_SUPPRESS_WARN . auto/have

have=NGX_SMP . auto/have