diff --git a/gtsam/3rdparty/metis-5.1.0/GKlib/GKlibSystem.cmake b/gtsam/3rdparty/metis-5.1.0/GKlib/GKlibSystem.cmake
index 3fcc29108..7ea5bab94 100644
--- a/gtsam/3rdparty/metis-5.1.0/GKlib/GKlibSystem.cmake
+++ b/gtsam/3rdparty/metis-5.1.0/GKlib/GKlibSystem.cmake
@@ -33,7 +33,7 @@ if(CMAKE_COMPILER_IS_GNUCC)
       set(GKlib_COPTIONS "${GKlib_COPTIONS} -fPIC")
   endif(NOT MINGW)
 # GCC warnings.
-  set(GKlib_COPTIONS "${GKlib_COPTIONS} -Wall -pedantic -Wno-unused-but-set-variable -Wno-unused-variable -Wno-unknown-pragmas")
+  set(GKlib_COPTIONS "${GKlib_COPTIONS} -Wall -pedantic -Wno-unused-variable -Wno-unknown-pragmas")
 elseif(${CMAKE_C_COMPILER_ID} MATCHES "Sun")
 # Sun insists on -xc99.
   set(GKlib_COPTIONS "${GKlib_COPTIONS} -xc99")