Example generated config:
#ifndef _RULES_AUTOCONF_CONFIG_H
#define _RULES_AUTOCONF_CONFIG_H
#define HAVE_ATTR_XATTR_H 0
#define HAVE_ERRNO_H 1
#define HAVE_FCNTL_H 1
#define HAVE_GRP_H 1
#define HAVE_IO_H 0
#define HAVE_LIMITS_H 1
#define HAVE_LINUX_FS_H 0
#define HAVE_PATHS_H 1
#define HAVE_PWD_H 1
#define HAVE_STDINT_H 1
#define HAVE_STRING_H 1
#define HAVE_SYS_STAT_H 1
#define HAVE_SYS_TYPES_H 1
#define HAVE_SYS_XATTR_H 1
#define HAVE_UNISTD_H 1
#define HAVE_WCHAR_H 1
#endif // _RULES_AUTOCONF_CONFIG_H