Remove some unused funcs & declarations

Removing more unused functions, and moving a declaration in fonts.h
to fonts.c, since it's not used externally (reliable_read()).

src/fonts.c

@@ -1,7 +1,7 @@
 /*
   fonts.c
 
-  Copyright (c) 2009-2014
+  Copyright (c) 2009-2017
   http://www.tuxpaint.org/
 
   This program is free software; you can redistribute it and/or modify
@@ -157,6 +157,10 @@ unsigned text_size = 4;         // initial text size
 
 int button_label_y_nudge;
 
+#ifdef FORKED_FONTS
+static void reliable_read(int fd, void *buf, size_t count);
+#endif
+
 
 #ifndef NO_SDLPANGO
 static TuxPaint_Font *try_alternate_font(int size)