Imported a model file for Coverity Scan to reduce false positives.

In general, any function declared with the 'ecl_attr_noreturn'
attribute might need to be defined to call __coverity_panic__() here.

See: https://scan.coverity.com/tune

src/c/coverity/model.c

@@ -0,0 +1,33 @@
+/* This is free and unencumbered software released into the public domain. */
+
+/**
+ * Coverity Scan model for ECL.
+ *
+ * This is a modeling file for the Coverity Scan static analysis service.
+ * Modeling helps to avoid false positives. Some rules for model files:
+ *
+ * - A model file cannot import any header files.
+ * - Therefore only built-in standard language symbols are available;
+ *   for example, `char`, `int`, and `void` are defined, `NULL` isn't.
+ * - Modeling doesn't require genuine definitions for structs and typedefs.
+ *   Typedefs that expand to rudimentary structs will suffice.
+ * - Uninitialized local pointers are not errors, but rather signify that
+ *   a variable could either be `NULL` or point at some data.
+ *
+ * Note that Coverity Scan doesn't automatically pick up changes to this
+ * file. New versions of the model file must be uploaded by an admin at:
+ * https://scan.coverity.com/projects/3235?tab=analysis_settings
+ *
+ * @author Arto Bendiken <arto@bendiken.net>
+ * @see    https://scan.coverity.com/tune
+ */
+
+#define NULL ((void*)0)
+
+typedef void* cl_object;
+typedef int cl_narg;
+
+void
+FEwrong_type_nth_arg(cl_object function, cl_narg narg, cl_object value, cl_object type) {
+  __coverity_panic__();
+}