diff -uNr metis-5.1.0_old/GKlib/GKlibSystem.cmake metis-5.1.0/GKlib/GKlibSystem.cmake
--- metis-5.1.0_old/GKlib/GKlibSystem.cmake	2013-12-04 20:05:16.775347144 +0100
+++ metis-5.1.0/GKlib/GKlibSystem.cmake	2013-12-04 20:06:34.111345064 +0100
@@ -33,7 +33,10 @@
       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 "${GKlib_COPTIONS} -Wall -pedantic -Wno-unused-variable -Wno-unknown-pragmas")
+  if(GCC_COMPILER_VERSION VERSION_GREATER 4.3)
+    set(GKlib_COPTIONS "${GKlib_COPTIONS} -Wno-unused-but-set-variable")
+  endif()
 elseif(${CMAKE_C_COMPILER_ID} MATCHES "Sun")
 # Sun insists on -xc99.
   set(GKlib_COPTIONS "${GKlib_COPTIONS} -xc99")