Fix multiple definitions for GCC10

include/gfx/main.h

@@ -83,7 +83,7 @@ struct Mapfile {
 	int size;
 };
 
-int depth, colors;
+extern int depth, colors;
 
 #include "gfx/makepng.h"
 #include "gfx/gb.h"

src/gfx/gb.c

@@ -10,7 +10,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 
-#include "gfx/main.h"
+#include "gfx/gb.h"
 
 void transpose_tiles(struct GBImage *gb, int width)
 {

src/gfx/main.c

@@ -15,6 +15,8 @@
 #include "extern/getopt.h"
 #include "version.h"
 
+int depth, colors;
+
 /* Short options */
 static char const *optstring = "Aa:CDd:Ffhmo:Pp:Tt:uVvx:";
 

src/gfx/makepng.c

@@ -11,7 +11,7 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include "gfx/main.h"
+#include "gfx/makepng.h"
 
 static void initialize_png(struct PNGImage *img, FILE * f);
 static struct RawIndexedImage *indexed_png_to_raw(struct PNGImage *img);