fixed a few problems detected by Xcode 4.2.1

modules/core/include/opencv2/core/mat.hpp

@@ -1089,7 +1089,6 @@ template<typename T1, typename T2, typename Op> inline void
 process( const Mat_<T1>& m1, Mat_<T2>& m2, Op op )
 {
     int y, x, rows = m1.rows, cols = m1.cols;
-    int c1 = m1.channels(), c2 = m2.channels();
 
     CV_DbgAssert( m1.size() == m2.size() );
 

modules/core/include/opencv2/core/opengl_interop.hpp

@@ -103,13 +103,13 @@ namespace cv
 
         inline Usage usage() const { return usage_; }
 
+        class Impl;
     private:
         int rows_;
         int cols_;
         int type_;
         Usage usage_;
 
-        class Impl;
         Ptr<Impl> impl_;
     };
 
@@ -150,12 +150,12 @@ namespace cv
         inline int elemSize() const { return CV_ELEM_SIZE(type_); }
         inline int elemSize1() const { return CV_ELEM_SIZE1(type_); }
 
+        class Impl;
     private:
         int rows_;
         int cols_;
         int type_;
 
-        class Impl;
         Ptr<Impl> impl_;
     };