Upgrade versions of vendored libs

vendor/github.com/DataDog/zstd/debug.h

@@ -33,10 +33,6 @@
 #ifndef DEBUG_H_12987983217
 #define DEBUG_H_12987983217
 
-#if defined (__cplusplus)
-extern "C" {
-#endif
-
 
 /* static assert is triggered at compile time, leaving no runtime artefact.
  * static assert only works with compile-time constants.
@@ -109,11 +105,6 @@ extern int g_debuglevel; /* the variable is only declared,
 #  define DEBUGLOG(l, ...) do { } while (0)    /* disabled */
 #endif
 
-
-#if defined (__cplusplus)
-}
-#endif
-
 #endif /* DEBUG_H_12987983217 */
 
 #endif /* USE_EXTERNAL_ZSTD */