restrict FreeType headers to a single translation unit (TextureFont.cpp)

This means we can remove some ugly #undefs from other files, and generally
avoid polluting the global namespace so much.

Fixes #1203

src/FileSourceZip.cpp

@@ -11,8 +11,6 @@ extern "C" {
 #include "miniz/miniz.h"
 }
 
-#undef FT_FILE // TODO FileInfo::FT_FILE is conflicting with a FreeType def; undefine it for now
-
 namespace FileSystem {
 
 FileSourceZip::FileSourceZip(FileSourceFS &fs, const std::string &zipPath) : FileSource(zipPath), m_archive(0)

src/FileSystem.cpp

@@ -10,8 +10,6 @@
 #include <iterator>
 #include <stdexcept>
 
-#undef FT_FILE // XXX FileInfo::FT_FILE is conflicting with a FreeType def; undefine it for now
-
 namespace FileSystem {
 
 	static FileSourceFS dataFilesApp(GetDataDir(), true);

src/text/TextureFont.cpp

@@ -8,10 +8,16 @@
 #include "graphics/VertexArray.h"
 #include "TextSupport.h"
 #include "utils.h"
-#include <algorithm>
 
+#include <ft2build.h>
+#include FT_FREETYPE_H
+#include FT_STROKER_H
 #include FT_GLYPH_H
 
+#undef FT_FILE // defined by FreeType, conflicts with a symbol name from FileSystem
+
+#include <algorithm>
+
 static const int ATLAS_SIZE = 1024;
 
 namespace Text {

src/text/TextureFont.h

@@ -12,12 +12,16 @@
 #include "graphics/VertexArray.h"
 #include "graphics/RenderState.h"
 
-#include <ft2build.h>
-#include FT_FREETYPE_H
-#include FT_STROKER_H
-
 namespace FileSystem { class FileData; }
 
+// forward declarations for FreeType types
+struct FT_FaceRec_;
+struct FT_LibraryRec_;
+struct FT_StrokerRec_;
+typedef struct FT_FaceRec_ *FT_Face;
+typedef struct FT_LibraryRec_ *FT_Library;
+typedef struct FT_StrokerRec_ *FT_Stroker;
+
 namespace Text {
 
 class TextureFont : public RefCounted {

src/win32/FileSystemWin32.cpp

@@ -11,9 +11,6 @@
 #include <algorithm>
 #include <cerrno>
 
-// I hate macros. I just hate them. Hate hate hate.
-#undef FT_FILE
-
 #include <windows.h>
 // GetPiUserDir() needs these
 #include <shlobj.h>