Ubuntu 12.04 build fixes

src/FreetypeRenderer.h

@@ -86,7 +86,7 @@ public:
         double size, spacing, fn;
 	std::string text, font, direction, language, script, halign, valign;
         
-        friend FreetypeRenderer;
+        friend class FreetypeRenderer;
     };
     
     FreetypeRenderer();

src/PlatformUtils.cc

@@ -2,6 +2,7 @@
 
 #include "PlatformUtils.h"
 #include "boosty.h"
+#include <Eigen/Core>
 
 extern std::vector<std::string> librarypath;
 

src/textnode.h

@@ -25,5 +25,5 @@ public:
 	virtual FreetypeRenderer::Params get_params() const;
 private:
 	FreetypeRenderer::Params params;
-	friend TextModule;
+	friend class TextModule;
 };