Fix cimport: function pointers void(void) are passed as void function().

hellogl.nt

@@ -1,25 +1,16 @@
 module hellogl;
 
-extern(C) void glClear(int);
-extern(C) void glBegin(int);
-extern(C) void glVertex3f(float, float, float);
-extern(C) void glEnd();
-extern(C) void glFlush();
-
-extern(C) void glutInit(int* argc, char** argv);
-extern(C) void glutInitDisplayMode(int);
-extern(C) void glutInitWindowSize(int, int);
-extern(C) void glutCreateWindow(char*);
-extern(C) void glutDisplayFunc(void function());
-extern(C) void glutMainLoop();
+macro import std.macro.cimport;
+import c_header("GL/gl.h");
+import c_header("GL/glut.h");
 
 pragma(lib, "GL");
 pragma(lib, "glut");
 
 void displayMe()
 {
-    glClear(0x4000);
-    glBegin(0x0009);
+    glClear(GL_COLOR_BUFFER_BIT);
+    glBegin(GL_POLYGON);
         glVertex3f(0.0f, 0.0f, 0.0f);
         glVertex3f(0.5f, 0.0f, 0.0f);
         glVertex3f(0.5f, 0.5f, 0.0f);

src/std/macro/cimport.nt

@@ -344,6 +344,13 @@ class CParserHelper {
                     }
                     params ~= notNull!ASTSymbol(arg.type);
                 }
+                if (params.length == 1) {
+                    if (auto basicType = params[0].instanceOf(ASTBasicType)) {
+                        if (basicType.name == "void") {
+                            params = [];
+                        }
+                    }
+                }
                 parser.commit;
                 return (new ASTFunctionPointer(current, params, start), name);
             }