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+README_zOS.txt for version 7.4 of Vim: Vi IMproved.
+
+This readme explains how to build Vim on z/OS.  Formerly called OS/390.
+See "README.txt" for general information about Vim.
+
+Most likely there are not many users out there using Vim on z/OS. So chances
+are good, that some bugs are still undiscovered.
+
+Getting the source to z/OS:
+==========================
+
+First get the source code in one big tar file and ftp it a binary to z/OS. If
+the tar file is initially compressed with gzip (tar.gz) or bzip2 (tar.bz2)
+uncompress it on your PC, as this tools are (most likely) not available on the
+mainframe.
+
+To reduce the size of the tar file you might compress it into a zip file. On
+z/OS Unix you might have the command "jar" from java to uncompress a zip. Use:
+        jar xvf <zip file name>
+
+Unpack the tar file on z/OS with 
+        pax -o from=ISO8859-1,to=IBM-1047 -rf vim.tar
+
+Note: The Vim source contains a few bitmaps etc which will be destroyed by
+this command, but these files are not needed on zOS (at least not for the
+console version).
+
+
+Compiling:
+==========
+
+Vim can be compiled with or without GUI support. For 7.4 only the compilation
+without GUI was tested. Below is a section about compiling with X11 but this
+is from an earlier version of Vim.
+
+Console only:
+-------------
+
+If you build VIM without X11 support, compiling and building is nearly
+straightforward. 
+
+Change to the vim directory and do:
+
+    # Don't use c89!
+    # Allow intermixing of compiler options and files.
+
+    $ export CC=cc
+    $ export _CC_CCMODE=1
+    $./configure --with-features=big --without-x --enable-gui=no
+    $ cd src
+    $ make
+
+      There may be warnings:
+        - include files not found (libc, sys/param.h, ...)
+        - Redeclaration of ... differs from ...
+        -- just ignore them.
+
+    $ make test
+
+      This will produce lots of garbage on your screen (including error
+      messages). Don't worry.
+
+      If the test stops at one point in vim (might happen in test 11), just
+      press :q!
+
+      Expected test failures:
+        11: If you don't have gzip installed
+        24: test of backslash sequences in regexp are ASCII dependent
+        42: Multibyte is not supported on z/OS
+        55: ASCII<->EBCDIC sorting
+        57: ASCII<->EBCDIC sorting
+        58: Spell checking is not supported with EBCDIC
+        71: Blowfish encryption doesn't work
+
+    $ make install
+
+
+With X11:
+---------
+
+WARNING: This instruction was not tested with Vim 7.4.
+
+There are two ways for building VIM with X11 support. The first way is simple
+and results in a big executable (~13 Mb), the second needs a few additional
+steps and results in a much smaller executable (~4.5 Mb). This examples assume
+you want Motif.
+
+  The easy way:
+    $ export CC=cc
+    $ export _CC_CCMODE=1
+    $ ./configure --enable-max-features --enable-gui=motif
+    $ cd src
+    $ make
+
+    With this VIM is linked statically with the X11 libraries.
+
+  The smarter way:
+    Make VIM as described above. Then create a file named 'link.sed' with the
+    following content (see src/link.390):
+
+	s/-lXext  *//g
+	s/-lXmu  *//g
+	s/-lXm	*/\/usr\/lib\/Xm.x /g
+	s/-lX11  */\/usr\/lib\/X11.x /g
+	s/-lXt	*//g
+	s/-lSM	*/\/usr\/lib\/SM.x /g
+	s/-lICE  */\/usr\/lib\/ICE.x /g
+
+    Then do:
+    $ rm vim
+    $ make
+
+    Now Vim is linked with the X11-DLLs.
+
+    See the Makefile and the file link.sh on how link.sed is used.
+
+