Turn off unused-parameter compile warning.

Signed-off-by: Ben Tyner <ben.tyner@ibm.com>
Change-Id: I6e989441d7fb73a3b368ffa18191d45c2f01b4bd
diff --git a/meson.build b/meson.build
index 1fcdd95..59278b1 100644
--- a/meson.build
+++ b/meson.build
@@ -3,8 +3,9 @@
         default_options: [
             'warning_level=3',
             'werror=true',
-            'cpp_std=c++11'
-        ])
+            'cpp_std=c++11',
+            'cpp_args=-Wno-unused-parameter'
+       ])
 
 incdir = [include_directories('src')]