[SV 62654] Support GNU Make on z/OS

Original patches provided by Igor Todorovski <itodorov@ca.ibm.com>
Reworked by Paul Smith <psmith@gnu.org>.
Thanks to IBM for providing a test system.

* NEWS: Announce support.
* AUTHORS: Ditto.
* README.zOS: Provide details on building GNU Make on z/OS.
* build.sh (get_mk_var): z/OS sh has a strange bug which causes it to
generate extra lines of output: rework the function to print output
as we compute it instead of collecting it into a variable, which
works around this bug.
* src/makeint.h: Declare MK_OS_ZOS if we're building for z/OS.
* src/arscan.c: Don't include <ar.h> on z/OS.
* src/job.c: We can't change environ in ASCII mode on z/OS.
* src/main.c: Ditto.  Also we can't use pselect() on z/OS.
* src/posixos.c: pselect() seems to hang on z/OS: don't use it.
* tests/run_make_tests.pl: Handle different exit codes on z/OS.
* tests/test_driver.pl: Preserve some special z/OS env.vars.
Add special checks to output comparisons when on z/OS.
* tests/scripts/features/archives: Don't validate names.  Don't
try to compile empty files as IBM compilers complain.
* tests/scripts/features/shell_assignment: Fix octal value of #.
* tests/scripts/features/temp_stdin: Don't print "term".
* tests/scripts/functions/shell: Handle shell exit codes.
* tests/scripts/targets/ONESHELL: Ditto.
* tests/scripts/targets/POSIX: sh -x prints differently.
* tests/scripts/variables/SHELL: Ditto.

1 files changed, 83 insertions, 0 deletions

diff --git a/README.zOS b/README.zOS
new file mode 100644
index 00000000..7ff50659
--- /dev/null
+++ b/README.zOS
@@ -0,0 +1,83 @@
+                                                                     -*-text-*-
+GNU Make has been ported to z/OS, tested on z/OS V2R4.
+
+
+PREREQUISITES
+-------------
+Building GNU Make requires certain tools be installed on your z/OS system.
+These tools can be downloaded from: https://github.com/ZOSOpenTools
+For detailed instructions on how to set up these tools, visit
+https://zosopentools.github.io/meta/#/Guides/Pre-req
+
+You will need curl, tar, and gzip to download and unpack the GNU Make release
+package, but presumably you've already worked this out if you're reading this
+document!
+
+You will need the IBM C/C++ compiler.  You can download a web deliverable
+add-on feature to your XL C/C++ compiler here:
+https://www-40.ibm.com/servers/resourcelink/svc00100.nsf/pages/xlCC++V241ForZOsV24
+
+Alternatively, you can install and manage C/C++ for Open Enterprise Languages
+on z/OS using RedHat OpenShift Container Platform and IBM Z and Cloud
+Modernization Stack.
+
+GNU Make has a dependency on the ZOSLIB library, which is documented here:
+https://zosopentools.github.io/meta/#/Guides/Zoslib.
+
+To obtain the latest release of zoslib, you can download it from here:
+https://github.com/ZOSOpenTools/zoslibport/releases.
+
+
+BUILDING
+--------
+If you are trying to build from a checked-out Git workspace, see README.git.
+
+Before building GNU Make, you will need to ensure that the following
+environment variables are set, to turn on z/OS enhanced ASCII support:
+
+  export _BPXK_AUTOCVT=ON
+  export _CEE_RUNOPTS="$_CEE_RUNOPTS FILETAG(AUTOCVT,AUTOTAG) POSIX(ON)"
+  export _TAG_REDIR_ERR=txt
+  export _TAG_REDIR_IN=txt
+  export _TAG_REDIR_OUT=txt
+
+To ensure proper functioning of xlclang, set the following environment
+variables before building:
+
+  export _CC_CCMODE=1
+  export _C89_CCMODE=1
+  export _CXX_CCMODE=1
+
+Set PATH_TO_ZOSLIB to the location of your zoslib installation; e.g.:
+
+  PATH_TO_ZOSLIB=$HOME/zopen/prod/zoslib
+
+Invoke ./configure as follows:
+
+  ./configure \
+      CC=xlclang \
+      CPPFLAGS="-DNSIG=42 -D_XOPEN_SOURCE=600 -D_ALL_SOURCE -D_OPEN_SYS_FILE_EXT=1 -D_AE_BIMODAL=1 -D_ENHANCED_ASCII_EXT=0xFFFFFFF -DZOSLIB_OVERRIDE_CLIB=1" \
+      CFLAGS="-qascii -std=gnu11 -qnocsect -qenum=int -I$PATH_TO_ZOSLIB/include" \
+      LDFLAGS="-L$PATH_TO_ZOSLIB/lib" \
+      LIBS="-lzoslib $PATH_TO_ZOSLIB/lib/CXXRT64.x"
+
+If you have an instance of make already available you can build with:
+
+  make
+
+If not, you can build with:
+
+  ./build.sh
+
+
+TESTING
+-------
+To run the regression tests you'll need to install Perl and enable it.
+Then you can run:
+
+  ./make check
+
+
+INSTALLING
+----------
+Copy the "make" program to wherever you want it to be installed, on your PATH.