Support packed struct DPI imports, bug1190.

src/V3Ast.h

@@ -396,7 +396,7 @@ public:
 	return (m_e==LOGIC || m_e==BIT);
     }
     bool isDpiUnsupported() const {
-	return (m_e==LOGIC || m_e==TIME);
+	return (m_e==TIME);
     }
     bool isDpiUnsignable() const {  // Can add "unsigned" to DPI
 	return (m_e==BYTE || m_e==SHORTINT || m_e==INT || m_e==LONGINT || m_e==INTEGER);

src/V3Delayed.cpp

@@ -158,7 +158,7 @@ private:
 	if (oldactivep->sensesp() != m_activep->sensesp()) {
 	    if (!varrefp->varp()->fileline()->warnIsOff(V3ErrorCode::MULTIDRIVEN)
 		&& !varrefp->varp()->user2()) {
-		varrefp->varp()->v3warn(MULTIDRIVEN,"Signal has multiple driving blocks: "<<varrefp->varp()->prettyName()<<endl
+		varrefp->varp()->v3warn(MULTIDRIVEN,"Signal has multiple driving blocks with different clocking: "<<varrefp->varp()->prettyName()<<endl
 					<<varrefp->warnMore()<<"... Location of first driving block"<<endl
 					<<oldactivep->warnMore()<<"... Location of other driving block");
 		varrefp->varp()->user2(true);

src/V3Task.cpp

@@ -938,6 +938,8 @@ private:
 			if (!portp->basicp() || portp->basicp()->keyword().isDpiUnsupported()) {
 			    portp->v3error("Unsupported: DPI argument of type "<<portp->basicp()->prettyTypeName()<<endl
 					   <<portp->warnMore()<<"... For best portability, use bit, byte, int, or longint");
+			    // We don't warn on logic either, although the 4-stateness is lost.
+			    // That's what other simulators do.
 			}
 		    }
 		} else {