--- a/packet.c	Sat Aug 12 20:51:58 2017 +0200
+++ b/packet.c	Sat Aug 19 17:16:13 2017 +0200
@@ -49,7 +49,7 @@
 #define ZLIB_COMPRESS_EXPANSION (((RECV_MAX_PAYLOAD_LEN/16384)+1)*5 + 6)
 #define ZLIB_DECOMPRESS_INCR 1024
 #ifndef DISABLE_ZLIB
-static buffer* buf_decompress(buffer* buf, unsigned int len);
+static buffer* buf_decompress(const buffer* buf, unsigned int len);
 static void buf_compress(buffer * dest, buffer * src, unsigned int len);
 #endif
 
@@ -367,7 +367,7 @@
 
 #ifndef DISABLE_ZLIB
 /* returns a pointer to a newly created buffer */
-static buffer* buf_decompress(buffer* buf, unsigned int len) {
+static buffer* buf_decompress(const buffer* buf, unsigned int len) {
 
 	int result;
 	buffer * ret;