--- a/configure	Sun Feb 22 18:44:48 2015 +0100
+++ b/configure	Tue Feb 24 15:22:09 2015 +0000
@@ -138,6 +138,7 @@
       ;;
    --libdir=*)
       LIBDIR="$value"
+      LIBDIR_SET=yes
       ;;
    --datadir=*)
    	DATADIR="$value"
@@ -212,6 +213,11 @@
    fi
 fi
 
+if [ "$PREFIX_SET" = "yes" -a ! "$LIBDIR_SET" = "yes" ]
+then
+   LIBDIR=$PREFIX/lib
+fi
+
 find_program() {
    path="$PATH"
    item="`echo "$path" | sed 's/\([^:]*\):.*/\1/'`"