Help clang static analyzer.

libs/ardour/mtdm.cc

@@ -17,6 +17,7 @@
 */
 
 #include <math.h>
+#include <assert.h>
 
 #include "ardour/mtdm.h"
 
@@ -58,6 +59,7 @@ int MTDM::process (size_t len, float *ip, float *op)
     float  vip, vop, a, c, s;
     Freq   *F;
 		float peak = 0;
+		assert (len > 0);
 
     while (len--)
     {

libs/audiographer/src/general/analyser.cc

@@ -31,6 +31,7 @@ Analyser::Analyser (float sample_rate, unsigned int channels, framecnt_t bufsize
 	, _pos (0)
 {
 	assert (bufsize % channels == 0);
+	assert (bufsize > 1);
 	//printf ("NEW ANALYSER %p r:%.1f c:%d f:%ld l%ld\n", this, sample_rate, channels, bufsize, n_samples);
 	if (channels > 0 && channels <= 2) {
 		using namespace Vamp::HostExt;