--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/zlib/os400/README400	Mon Sep 15 11:44:09 2025 +0200
@@ -0,0 +1,48 @@
+        ZLIB version 1.3.1 for OS/400 installation instructions
+
+1) Download and unpack the zlib tarball to some IFS directory.
+   (i.e.: /path/to/the/zlib/ifs/source/directory)
+
+   If the installed IFS command supports gzip format, this is straightforward,
+else you have to unpack first to some directory on a system supporting it,
+then move the whole directory to the IFS via the network (via SMB or FTP).
+
+2) Edit the configuration parameters in the compilation script.
+
+        EDTF STMF('/path/to/the/zlib/ifs/source/directory/os400/make.sh')
+
+Tune the parameters according to your needs if not matching the defaults.
+Save the file and exit after edition.
+
+3) Enter qshell, then work in the zlib OS/400 specific directory.
+
+        QSH
+        cd /path/to/the/zlib/ifs/source/directory/os400
+
+4) Compile and install
+
+        sh make.sh
+
+The script will:
+- create the libraries, objects and IFS directories for the zlib environment,
+- compile all modules,
+- create a service program,
+- create a static and a dynamic binding directory,
+- install header files for C/C++ and for ILE/RPG, both for compilation in
+  DB2 and IFS environments.
+
+That's all. 
+
+
+Notes:  For OS/400 ILE RPG programmers, a /copy member defining the ZLIB
+                API prototypes for ILE RPG can be found in ZLIB/H(ZLIB.INC).
+                In the ILE environment, the same definitions are available from
+                file zlib.inc located in the same IFS include directory as the
+                C/C++ header files.
+                Please read comments in this member for more information.
+
+        Remember that most foreign textual data are ASCII coded: this
+                implementation does not handle conversion from/to ASCII, so
+                text data code conversions must be done explicitly.
+
+        Mainly for the reason above, always open zipped files in binary mode.