Environment

on a SLES 12 SP1 on Power server
rb3test:~ # uname -a
Linux rb3test 4.4.90-92.45-default #1 SMP Tue Oct 24 15:03:15 UTC 2017 (1094ae5) ppc64le ppc64le ppc64le GNU/Linux

fresh build jruby
rb3test:~ # /tmp/jruby-9.1.14.0/bin/jruby -v
jruby 9.1.14.0 (2.3.3) 2017-12-06 fffffff OpenJDK 64-Bit Server VM 25.151-b12 on 1.8.0_151-b12 +jit [linux-ppc64le]

rb3test:/tmp/jruby-9.1.14.0 # ./mvnw
Downloading https://repo1.maven.org/maven2/org/apache/maven/apache-maven/3.3.9/apache-maven-3.3.9-bin.zip
.....
[INFO] Reactor Summary:
[INFO]
[INFO] JRuby .............................................. SUCCESS [ 4.791 s]
[INFO] JRuby Core ......................................... SUCCESS [ 45.169 s]
[INFO] JRuby Lib Setup .................................... SUCCESS [ 30.720 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 01:41 min
[INFO] Finished at: 2017-12-06T07:46:04+01:00
[INFO] Final Memory: 83M/614M
[INFO] ---------------------------------------------------------------------

standard installed ruby from Suse repo
rb3test:~ # ruby -v
ruby 2.1.9p490 (2016-03-30 revision 54437) [powerpc64le-linux-gnu]

rb3test:~ # rpm -qa | grep ruby
ruby2.1-devel-2.1.9-18.1.ppc64le
ruby2.1-rubygem-cfa_grub2-0.5.3-2.3.1.ppc64le
libstorage-ruby-2.26.10-13.5.ppc64le
ruby2.1-rubygem-ruby-augeas-0.5.0-1.40.ppc64le
yast2-ruby-bindings-3.1.51.2-9.3.1.ppc64le
ruby2.1-rubygem-gem2rpm-0.10.1-4.1.ppc64le
ruby2.1-2.1.9-18.1.ppc64le
ruby2.1-rubygem-bundler-1.7.3-3.8.ppc64le
ruby2.1-rubygem-cheetah-0.5.0-4.1.ppc64le
ruby2.1-rubygem-fast_gettext-0.9.2-1.1.ppc64le
ruby2.1-rubygem-cfa-0.3.1-1.1.ppc64le
ruby2.1-stdlib-2.1.9-18.1.ppc64le
ruby-2.1-1.6.ppc64le
ruby2.1-rubygem-abstract_method-1.2.1-4.1.ppc64le
ruby-common-2.1-19.1.noarch
libruby2_1-2_1-2.1.9-18.1.ppc64le
ruby2.1-rubygem-ruby-dbus-0.9.3-3.6.ppc64le

Expected Behavior

rb3test:~ # /tmp/jruby-9.1.14.0/bin/jruby -r syslog -e 'puts "OK"'
OK

like by ruby
rb3test:~ # ruby -r syslog -e 'puts "OK"'
OK

Actual Behavior

rb3test:~ # /tmp/jruby-9.1.14.0/bin/jruby -d -r syslog -e 'puts "OK"'
Exception LoadError' at org/jruby/RubyKernel.java:955 - no such file to load -- /tmp/jruby-9.1.14.0/lib/ruby/stdlib/ffi/platform/powerpc64le-linux/syslog Exception LoadError' at /tmp/jruby-9.1.14.0/lib/ruby/stdlib/syslog.rb:20 - Syslog not supported on this platform
Exception `LoadError' at /tmp/jruby-9.1.14.0/lib/ruby/stdlib/syslog.rb:20 - Syslog not supported on this platform

rb3test:~ # ruby -r syslog -e 'puts "OK"'
OK

seems powerpc64le-linux is not implemented

also strange ruby show platform powerpc64le-linux-gnu
jruby show linux-ppc64le but search for powerpc64le-linux