Etc::SC_OPEN_MAX not defined

[donoghuc]

Environment Information
Jruby

[root@outward-unison bin]# jruby -v
jruby 9.2.11.1 (2.5.7) 2020-03-25 b1f55b1a40 OpenJDK 64-Bit Server VM 11.0.7+10-LTS on 11.0.7+10-LTS +jit [linux-x86_64]

Java

[root@outward-unison bin]# java -version
openjdk version "11.0.7" 2020-04-14 LTS
OpenJDK Runtime Environment 18.9 (build 11.0.7+10-LTS)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.7+10-LTS, mixed mode, sharing)

OS

[root@outward-unison bin]# cat /etc/os-release 
NAME="CentOS Linux"
VERSION="8 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="8"
PLATFORM_ID="platform:el8"
PRETTY_NAME="CentOS Linux 8 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:8"
HOME_URL="https://www.centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"

CENTOS_MANTISBT_PROJECT="CentOS-8"
CENTOS_MANTISBT_PROJECT_VERSION="8"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="8"

Expected Behavior
From these spec test it looks like the Etc::SC_OPEN_MAX constant should be defined:
https://github.com/jruby/jruby/blob/9.2.11.1/spec/ruby/library/etc/sysconf_spec.rb

Actual Behavior
Name error when trying to fetch the constant

irb(main):001:0> require 'etc'
=> true
irb(main):002:0> Etc.sysconf(Etc.const_get('SC_OPEN_MAX'))
Traceback (most recent call last):
        8: from ./irb:13:in `<main>'
        7: from org/jruby/RubyKernel.java:1189:in `catch'
        6: from org/jruby/RubyKernel.java:1189:in `catch'
        5: from org/jruby/RubyKernel.java:1442:in `loop'
        4: from org/jruby/RubyKernel.java:1048:in `eval'
        3: from (irb):2:in `evaluate'
        2: from org/jruby/RubyModule.java:3707:in `const_get'
        1: from org/jruby/RubyModule.java:3760:in `const_missing'
NameError (uninitialized constant Etc::SC_OPEN_MAX)

[donoghuc]

Thanks for the patch!