build macro ZSTD_DECODER_INTERNAL_BUFFER

just to make the topic more accessible for potential users.

lib/decompress/zstd_decompress_internal.h

@@ -106,10 +106,15 @@ typedef struct {
     size_t ddictPtrCount;
 } ZSTD_DDictHashSet;
 
-#ifndef ZSTD_LITBUFFEREXTRASIZE
-#define ZSTD_LITBUFFEREXTRASIZE    (1 << 16) /* extra buffer reduces amount of dst required to store litBuffer */
+#ifndef ZSTD_DECODER_INTERNAL_BUFFER
+#  define ZSTD_DECODER_INTERNAL_BUFFER  (1 << 16)
 #endif
 
+#define ZSTD_LBMAX (128 << 10)
+
+/* extra buffer, compensates amount of dst required to store litBuffer */
+#define ZSTD_LITBUFFEREXTRASIZE  MIN(ZSTD_DECODER_INTERNAL_BUFFER, ZSTD_LBMAX)
+
 typedef enum {
     ZSTD_not_in_dst = 0,  /* Stored entirely within litExtraBuffer */
     ZSTD_in_dst = 1,           /* Stored entirely within dst (in memory after current output write) */