Index: trunk/psLib/configure.ac
===================================================================
--- trunk/psLib/configure.ac	(revision 19035)
+++ trunk/psLib/configure.ac	(revision 19052)
@@ -197,6 +197,6 @@
     FFTW_THREADS=1
     PSLIB_LIBS="${PSLIB_LIBS=} -lfftw3f_threads"],
-   AC_MSG_WARN([FFTW version 3 not compiled with thread support (--enable-threads)])
-   )]
+   AC_MSG_WARN([FFTW version 3 not compiled with thread support (--enable-threads)]),[-lm]
+   )],[-lm]
 )