[multiple] quiet some clang-analyzer warnings

src/h2.c

@@ -1479,7 +1479,7 @@ h2_parse_frames (connection * const con)
              */
             if (cqlen < 9+flen) return 1; /* incomplete frame; go on */
             if (clen < 9+flen) {
-                clen = h2_frame_cq_compact(cq, 9+flen);
+                clen = h2_frame_cq_compact(cq, 9+flen); UNUSED(clen);
                 c = cq->first; /*(reload after h2_frame_cq_compact())*/
                 s = (uint8_t *)(c->mem->ptr + c->offset);
             }

src/mod_cgi.c

@@ -513,7 +513,7 @@ static int cgi_env_add(void *venv, const char *key, size_t key_len, const char *
 	dst = env->ptr + env->used;
 	memcpy(dst, key, key_len);
 	dst[key_len] = '=';
-	memcpy(dst + key_len + 1, val, val_len);
+	if (val_len) memcpy(dst + key_len + 1, val, val_len);
 	dst[key_len + 1 + val_len] = '\0';
 
 	if (env->osize == env->oused) {

src/mod_fastcgi.c

@@ -190,7 +190,7 @@ static int fcgi_env_add(void *venv, const char *key, size_t key_len, const char
 	dst = buffer_string_prepare_append(env, len);
 	memcpy(dst, len_enc, len_enc_len);
 	memcpy(dst + len_enc_len, key, key_len);
-	memcpy(dst + len_enc_len + key_len, val, val_len);
+	if (val_len) memcpy(dst + len_enc_len + key_len, val, val_len);
 	buffer_commit(env, len);
 
 	return 0;

src/t/test_request.c

@@ -29,6 +29,7 @@ static void run_http_request_parse(request_st * const r, int line, int status, c
     memcpy(hdrs, req, reqlen);
     hloffsets[0] = 1;
     hloffsets[1] = 0;
+    hloffsets[2] = 0;
     for (const char *n=req, *end=req+reqlen; (n=memchr(n,'\n',end-n)); ++n) {
         if (++hloffsets[0] >= sizeof(hloffsets)/sizeof(*hloffsets)) break;
         hloffsets[hloffsets[0]] = n - req + 1;