diff --git a/Source/cmMakefile.h b/Source/cmMakefile.h
index 808658338..8d4a2cb7f 100644
--- a/Source/cmMakefile.h
+++ b/Source/cmMakefile.h
@@ -52,6 +52,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 class cmFunctionBlocker;
 class cmCommand;
 class cmMakefileGenerator;
+class cmMakeDepend;
 
 /** \class cmMakefile
  * \brief Process the input CMakeLists.txt file.