fix compiler warnings on gcc 4.6.3, Debug build

Documentation/compiling/build-msw.txt

 Introduction
 ------------
-This document details how to build KiCad from source on Windows.  The current
-supported method of building KiCad on Windows systems is to use MinGW/MSYS.
-Other build systems such as Visual Studio and Eclipse can be used but your
-mileage may vary.  If you choose to build KiCad with one of the unsupported
-tools, please do not expect a great deal of help from the KiCad developers
-unless you want to be the person that supports the build tool.  If you add
-or remove any of the KiCad  build dependencies, please update this document.
+
+This document details how to build KiCad from source on Windows. The current
+supported method of building KiCad on Windows systems is to use MinGW,
+either from MSYS or cross compiling from Linux. Visual Studio is not
+supported, and don't ask about it, it is not supported and will not be.
+
+If you add or remove any of the KiCad build dependencies, please update this
+document.
 
 Install Build Tools
 -------------------

include/boost/polygon/detail/minkowski.hpp

@@ -30,13 +30,13 @@ struct minkowski_offset {
   static void convolve_two_point_sequences(polygon_set& result, itrT1 ab, itrT1 ae, itrT2 bb, itrT2 be) {
     if(ab == ae || bb == be)
       return;
-    point first_a = *ab;
+    // point first_a = *ab;
     point prev_a = *ab;
     std::vector<point> vec;
     polygon poly;
     ++ab;
     for( ; ab != ae; ++ab) {
-      point first_b = *bb;
+      // point first_b = *bb;
       point prev_b = *bb;
       itrT2 tmpb = bb;
       ++tmpb;

pcbnew/printout_controler.cpp

@@ -319,9 +319,10 @@ void BOARD_PRINTOUT_CONTROLLER::DrawPage()
     wxLogTrace( tracePrinting, wxT( "Logical origin:                   x=%d, y=%d" ),
                 offset.x, offset.y );
 
-#if defined(DEBUG)
+#if defined(wxUSE_LOG_TRACE)
     wxRect paperRect = GetPaperRectPixels();
-    wxLogTrace( tracePrinting, wxT( "Paper rectangle:                  left=%d, top=%d, right=%d, bottom=%d" ),
+    wxLogTrace( tracePrinting, wxT( "Paper rectangle:                  left=%d, top=%d, "
+                                    "right=%d, bottom=%d" ),
                 paperRect.GetLeft(), paperRect.GetTop(), paperRect.GetRight(),
                 paperRect.GetBottom() );
 
@@ -329,7 +330,8 @@ void BOARD_PRINTOUT_CONTROLLER::DrawPage()
     int devTop = dc->LogicalToDeviceY( drawRect.GetY() );
     int devRight = dc->LogicalToDeviceX( drawRect.GetRight() );
     int devBottom = dc->LogicalToDeviceY( drawRect.GetBottom() );
-    wxLogTrace( tracePrinting, wxT( "Final device rectangle:           left=%d, top=%d, right=%d, bottom=%d\n" ),
+    wxLogTrace( tracePrinting, wxT( "Final device rectangle:           left=%d, top=%d, "
+                                    "right=%d, bottom=%d\n" ),
                 devLeft, devTop, devRight, devBottom );
 #endif