--- a/ZipStream.st	Thu Jul 09 21:48:49 2020 +0100
+++ b/ZipStream.st	Tue Aug 25 09:35:11 2020 +0100
@@ -15,7 +15,7 @@
 
 CompressionStream subclass:#ZipStream
 	instanceVariableNames:''
-	classVariableNames:'Z_DEFLATED HEAD_OS_CODE HEAD_RESERVED HEAD_EXTRA_FIELD
+	classVariableNames:'Z_DEFLATED HEAD_RESERVED HEAD_EXTRA_FIELD
 		HEAD_ORIG_NAME HEAD_COMMENT HEAD_CRC GZ_MAGIC_ID'
 	poolDictionaries:''
 	category:'Streams-Compressed'
@@ -28,8 +28,8 @@
  * includes, defines, structure definitions
  * and typedefs come here.
  */
-#include "zlib.h"
-#include "zutil.h"
+#include <string.h>
+#include <zlib.h>
 
 typedef enum {
 	  e_opmode_unspecified          /* processing done */
@@ -148,12 +148,10 @@
     |z_deflated os_code|
 %{
     z_deflated = __MKSMALLINT( Z_DEFLATED );
-    os_code    = __MKSMALLINT( OS_CODE );
 %}.
 
     Z_DEFLATED            := z_deflated.
 
-    HEAD_OS_CODE          := os_code.
     HEAD_RESERVED         := 16rE0.     " bits 5..7:  reserved "
     HEAD_EXTRA_FIELD      := 16r04.     " bit 2 set:  extra field present "
     HEAD_ORIG_NAME        := 16r08.     " bit 3 set:  original file name present "
@@ -500,7 +498,7 @@
 			       , __intVal( level )
 			       , Z_DEFLATED
 			       , __intVal( windowBits )
-			       , DEF_MEM_LEVEL
+			       , 8
 			       , Z_DEFAULT_STRATEGY
 			       );
 
@@ -698,7 +696,7 @@
 	OBJ     _outObj = __INST( outputBytes );
 	OBJ     _inpObj = __INST( inputBytes  );
 
-	zmemzero( _zstream, sizeof(zstream_s) );
+	memset( _zstream, 0, sizeof(zstream_s) );
 
 	_zstream->in_ref           = (Bytef *) __externalBytesAddress( _inpObj );
 	_zstream->stream.next_in   = Z_NULL;
@@ -851,7 +849,7 @@
             ].
 
     "write OS code"
-    onStream nextPutByte:HEAD_OS_CODE.
+    onStream nextPutByte:3."assume Unix"
 ! !
 
 !ZipStream class methodsFor:'documentation'!