Added IPC support to attention handler

Created a listener thread that configures and starts the attention
gpio monitor. The listener remains resident in memory and accepts
run-time commands to configure (or stop) the attention handler.

Signed-off-by: Ben Tyner <ben.tyner@ibm.com>
Change-Id: I032fe25a49d43d91a1f7d41cc34318839cd7de05
diff --git a/meson.build b/meson.build
index 9edebbf..ef2b206 100644
--- a/meson.build
+++ b/meson.build
@@ -15,7 +15,11 @@
 subdir('analyzer')
 subdir('attn')
 
-executable('openpower-hw-diags', 'main.cpp', 'cli.cpp',
+pthread = declare_dependency(link_args : '-pthread')
+lrt = declare_dependency(link_args : '-lrt')
+
+executable('openpower-hw-diags', 'main.cpp', 'cli.cpp', 'listener.cpp',
+            dependencies : [lrt, pthread],
             link_with : [analyzer, attn],
             install : true)