Fix issues I created in rev 6442 (no issue on msys2/gcc5.3, but issues on Kubuntu 14.04/ gcc 4.8). I'll find a better fix later.

CMakeLists.txt

@@ -460,7 +460,7 @@ find_package( Cairo 1.8.8 REQUIRED )
 #
 # Note: Prior to Boost 1.59, the Boost context library is not built when compiling on windows
 #       with GCC.  You must patch the Boost sources.
-find_package( Boost 1.54.0 REQUIRED COMPONENTS context coroutine system thread )
+find_package( Boost 1.54.0 REQUIRED COMPONENTS context system thread )
 
 # Include MinGW resource compiler.
 include( MinGWResourceCompiler )

pcbnew/class_board.h

@@ -1216,10 +1216,10 @@ public:
      * of the via.
      * </p>
      * @param aPosition The wxPoint to HitTest() against.
-     * @param aLayer The layer to search.  Use -1 for a don't care.
+     * @param aLayer The layer to search.  Use -1 (LAYER_ID::UNDEFINED_LAYER) for a don't care.
      * @return VIA* A point a to the VIA object if found, else NULL.
      */
-    VIA* GetViaByPosition( const wxPoint& aPosition, LAYER_ID aLayer = LAYER_ID::UNDEFINED_LAYER ) const;
+    VIA* GetViaByPosition( const wxPoint& aPosition, LAYER_ID aLayer = LAYER_ID( -1 ) ) const;
 
     /**
      * Function GetPad