Improved the capabilities feature detection. Previously included file sys/capability.h mentioned in capset(2) man page, belongs to the libcap-dev package, which may not be installed on some Linux systems when compiling nginx. This prevented the capabilities feature from being detected and compiled on that systems. Now linux/capability.h system header is included instead. Since capset() declaration is located in sys/capability.h, now capset() syscall is defined explicitly in code using the SYS_capset constant, similarly to other Linux-specific features in nginx.

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_USER_H_INCLUDED_
#define _NGX_USER_H_INCLUDED_


#include <ngx_config.h>
#include <ngx_core.h>


typedef uid_t  ngx_uid_t;
typedef gid_t  ngx_gid_t;


ngx_int_t ngx_libc_crypt(ngx_pool_t *pool, u_char *key, u_char *salt,
    u_char **encrypted);


#endif /* _NGX_USER_H_INCLUDED_ */