Fix CVE-2023-2004 in freetype 2.12.1

Backport freetype/freetype@e6fda039a

Signed-off-by: Peter Shipton <[email protected]>

Author: pshipton

src/java.desktop/share/native/libfreetype/src/truetype/ttgxvar.c

@@ -42,6 +42,7 @@
 #include <ft2build.h>
 #include <freetype/internal/ftdebug.h>
 #include FT_CONFIG_CONFIG_H
+#include <freetype/internal/ftcalc.h>
 #include <freetype/internal/ftstream.h>
 #include <freetype/internal/sfnt.h>
 #include <freetype/tttags.h>
@@ -1140,7 +1141,7 @@
                 delta == 1 ? "" : "s",
                 vertical ? "VVAR" : "HVAR" ));
 
-    *avalue += delta;
+    *avalue = ADD_INT( *avalue, delta );
 
   Exit:
     return error;