Use cinttypes instead of inttypes.h

Fixes build on some compilers for some reason I fail to understand

src/gfx/convert.cpp

@@ -10,9 +10,9 @@
 
 #include <algorithm>
 #include <assert.h>
+#include <cinttypes>
 #include <errno.h>
 #include <fstream>
-#include <inttypes.h>
 #include <memory>
 #include <optional>
 #include <png.h>

src/gfx/main.cpp

@@ -10,8 +10,8 @@
 
 #include <algorithm>
 #include <assert.h>
+#include <cinttypes>
 #include <ctype.h>
-#include <inttypes.h>
 #include <limits>
 #include <numeric>
 #include <stdarg.h>

src/gfx/pal_packing.cpp

@@ -10,7 +10,7 @@
 
 #include <assert.h>
 #include <bitset>
-#include <inttypes.h>
+#include <cinttypes>
 #include <numeric>
 #include <optional>
 #include <queue>