HEADS UP: First go at cabalising hs-plugins build system. Bugs have been introduced though

plugins/Language/Hi/hschooks.c

@@ -0,0 +1,38 @@
+/*
+These routines customise the error messages
+for various bits of the RTS.  They are linked
+in instead of the defaults.
+*/
+
+#include <string.h>
+
+/* For GHC 4.08, we are relying on the fact that RtsFlags has
+ * compatibile layout with the current version, because we're
+ * #including the current version of RtsFlags.h below.  4.08 didn't
+ * ship with its own RtsFlags.h, unfortunately.   For later GHC
+ * versions, we #include the correct RtsFlags.h.
+ */
+
+#include "Rts.h"
+#include "RtsFlags.h"
+
+#include "HsFFI.h"
+
+HsInt
+plugin_strlen( HsAddr a )
+{
+    return (strlen((char *)a));
+}
+
+HsInt
+plugin_memcmp( HsAddr a1, HsAddr a2, HsInt len )
+{
+    return (memcmp((char *)a1, a2, len));
+}
+
+HsInt
+plugin_memcmp_off( HsAddr a1, HsInt i, HsAddr a2, HsInt len )
+{
+    return (memcmp((char *)a1 + i, a2, len));
+}
+