diff -up iaxclient-2.1beta3/configure.ac.DSO iaxclient-2.1beta3/configure.ac
--- iaxclient-2.1beta3/configure.ac.DSO 2010-02-10 14:59:13.713769339 -0500
+++ iaxclient-2.1beta3/configure.ac 2010-02-10 14:59:13.720763386 -0500
@@ -49,6 +49,9 @@ AC_CHECK_FUNCS([vsnprintf _vsnprintf])
AC_CHECK_FUNCS([srandomdev srandom srand48 random lrand48])
AC_CHECK_FUNCS(gettimeofday)
+# Implicit DSO linking fix
+AC_CHECK_LIB(m, sincos)
+
ACX_PTHREAD
AC_CHECK_PROG(have_pkg_config, pkg-config, yes, no)