A few bits of troff don't seem to be buggered anymore.
diff --git a/src/mkcommon b/src/mkcommon
index b950757..e99a261 100644
--- a/src/mkcommon
+++ b/src/mkcommon
@@ -3,6 +3,9 @@
 %.$O:	%.c
 	$CC $CFLAGS $stem.c
 
+%.$O:	%.cc
+	$CC $CFLAGS $stem.cc
+
 %.$O:	%.s
 	$AS $AFLAGS $stem.s