diff -urN qwt-6.0.1/src/src.pro qwt-6.0.1-patched/src/src.pro
--- qwt-6.0.1/src/src.pro	2011-08-02 01:33:53.000000000 +1100
+++ qwt-6.0.1-patched/src/src.pro	2012-04-28 18:05:44.666384280 +1100
@@ -212,6 +212,8 @@
         qwt_wheel.cpp
 }
 
+LIBS += -lrt
+
 # Install directives
 
 target.path    = $${QWT_INSTALL_LIBS}