Fix/re-enable SSE/SSE2 lpc optimisations.
diff --git a/configure.ac b/configure.ac
index f000a0b..ed9713b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -415,6 +415,11 @@
 		XIPH_ADD_CFLAGS([-fgnu89-inline])
 		fi
 
+	if test "x$asm_optimisation" = "xyes" ; then
+		XIPH_ADD_CFLAGS([-msse])
+		XIPH_ADD_CFLAGS([-msse2])
+		fi
+
 	fi
 
 XIPH_ADD_CFLAGS([-Wextra])