Must use textproc/libstemmer, because qcad links to the port if it is
installed.

Index: src/stemmer/RStemmer.cpp
--- src/stemmer/RStemmer.cpp.orig
+++ src/stemmer/RStemmer.cpp
@@ -18,7 +18,7 @@
  */
 #include <QDebug>
 
-#include "stemmer/include/libstemmer.h"
+#include <libstemmer.h>
 
 #include "RStemmer.h"
 
