Merge branch 'primitive_redefinition' of https://github.com/thasti/iverilog

- make primitive redefinition a warning, not an error
- make edge-sensitive ifnone a warning, not an error

This allows Icarus to be used to simulate designs using third-party
cell libraries that contain such things.

parse.y

@@ -5782,7 +5782,7 @@ specify_item
 		  pform_module_specify_path(tmp);
 		}
 	| K_ifnone specify_edge_path_decl ';'
-		{ yyerror(@1, "Sorry: ifnone with an edge-sensitive path is "
+		{ yywarn(@1, "Sorry: ifnone with an edge-sensitive path is "
 		              "not supported.");
 		  yyerrok;
 		}

parse_misc.cc

@@ -39,6 +39,11 @@ std::ostream& operator << (std::ostream&o, const YYLTYPE&loc)
       return o;
 }
 
+void VLwarn(const char*msg)
+{
+      warn_count += 1;
+      cerr << yylloc.text << ":" << yylloc.first_line << ": " << msg << endl;
+}
 
 void VLerror(const char*msg)
 {

parse_misc.h

@@ -59,6 +59,7 @@ extern int  VLlex();
 extern void VLerror(const char*msg);
 extern void VLerror(const YYLTYPE&loc, const char*msg, ...) __attribute__((format(printf,2,3)));
 #define yywarn VLwarn
+extern void VLwarn(const char*msg);
 extern void VLwarn(const YYLTYPE&loc, const char*msg);
 
 extern void destroy_lexor();

pform.cc

@@ -1847,7 +1847,7 @@ void pform_make_udp(perm_string name, list<perm_string>*parms,
 
 	// Put the primitive into the primitives table
       if (pform_primitives[name]) {
-	    VLerror("UDP primitive already exists.");
+	    VLwarn("UDP primitive already exists.");
 
       } else {
 	    PUdp*udp = new PUdp(name, parms->size());