diff --git a/cmake/Modules/Duplicates.cmake b/cmake/Modules/Duplicates.cmake
index d277e322..aee9f62e 100644
--- a/cmake/Modules/Duplicates.cmake
+++ b/cmake/Modules/Duplicates.cmake
@@ -22,23 +22,16 @@ endmacro (remove_duplicate_libraries module)
 
 # headers can be trimmed from the end, since adding a directory to
 # the list is an idempotent action
-macro (remove_duplicate_headers module)
-  if (DEFINED ${module}_INCLUDE_DIRS)
-	list (REMOVE_DUPLICATES ${module}_INCLUDE_DIRS)
-  endif (DEFINED ${module}_INCLUDE_DIRS)
-endmacro (remove_duplicate_headers module)
-
-# linker flags may not be specified at all
-macro (remove_duplicate_flags module)
-  if (DEFINED ${module}_LINKER_FLAGS)
-	list (REMOVE_DUPLICATES ${module}_LINKER_FLAGS)
-  endif (DEFINED ${module}_LINKER_FLAGS)
-endmacro (remove_duplicate_flags module)
+macro (remove_duplicate_var module suffix)
+  if (DEFINED ${module}_${suffix})
+	list (REMOVE_DUPLICATES ${module}_${suffix})
+  endif (DEFINED ${module}_${suffix})
+endmacro (remove_duplicate_var module suffix)
 
 # fix up both headers and libraries, in case two dependencies have
 # included the same second-level library independently
 macro (remove_dup_deps module)
-  remove_duplicate_headers (${module})
+  remove_duplicate_var (${module} INCLUDE_DIRS)
+  remove_duplicate_var (${module} LINKER_FLAGS)
   remove_duplicate_libraries (${module})
-  remove_duplicate_flags (${module})
 endmacro (remove_dup_deps module)
diff --git a/cmake/Modules/OpmFind.cmake b/cmake/Modules/OpmFind.cmake
index adaf60f7..1f0b1bfb 100644
--- a/cmake/Modules/OpmFind.cmake
+++ b/cmake/Modules/OpmFind.cmake
@@ -101,7 +101,7 @@ macro (find_and_append_package_to prefix name)
 	  if ("${var}" STREQUAL "LIBRARIES")
 		remove_duplicate_libraries (${prefix})
 	  else ("${var}" STREQUAL "LIBRARIES")
-		list (REMOVE_DUPLICATES ${prefix}_${var})
+		remove_duplicate_var (${prefix} ${var})
 	  endif ("${var}" STREQUAL "LIBRARIES")
 	endforeach (var)
 	# some libraries only define xxx_FOUND and not a corresponding HAVE_xxx