Clean up exported varyings and add support for querying program count from C/C++

module.cpp

@@ -607,6 +607,9 @@ lRecursiveCheckValidParamType(const Type *t, bool vectorOk) {
         return lRecursiveCheckValidParamType(pt->GetBaseType(), true);
     }
 
+    if (t->IsVaryingType() && !vectorOk)
+      return false;
+    else 
       return true;
 }
 
@@ -2340,8 +2343,6 @@ lGetVaryingDispatchType(FunctionTargetVariants &funcs) {
   return resultFuncTy;
 }
 
-#include <iostream>
-
 /** Create the dispatch function for an exported ispc function.
     This function checks to see which vector ISAs the system the
     code is running on supports and calls out to the best available

stdlib.ispc

@@ -5158,3 +5158,12 @@ __declspec(safe)
 static unmasked inline int16 avg_down(int16 a, int16 b) {
     return __avg_down_int16(a, b);
 }
+
+
+// Added so programmers can query programCount
+// at runtime from C/C++.
+// This is useful for using varying 
+// structures with exported functions
+export uniform int32 get_programCount() {
+  return programCount;
+}