Add os390.c

z/OS has extra startup needs like a couple other platforms, e.g. cygwin.
This adds a file that handles them.

Principally, z/OS files have extra status fields regarding "tags".
Files on this system may be encoded in different character sets, and
these fields describe them.  Hence the OS has within it the knowledge of
a file's encoding.  A file is "tagged" as being in a particular encoding
(or encodings plural; I have no idea how that works).  This file adds a
function to deal with them.

Author: IgorTodorovskiIBM

MANIFEST

@@ -5665,6 +5665,7 @@ os2/os2thread.h				pthread-like typedefs
 os2/perl2cmd.pl				Corrects installed binaries under OS/2
 os2/perlrexx.c				Support perl interpreter embedded in REXX
 os2/perlrexx.cmd			Test perl interpreter embedded in REXX
+os390/os390.c				z/OS specific code
 plan9/9front.patch			Plan9 port: patch for 9front-specific flavor of Plan 9
 plan9/aperl				Plan9 port: shell to make Perl error messages Acme-friendly
 plan9/arpa/inet.h			Plan9 port: replacement C header file

os390/os390.c

@@ -0,0 +1,57 @@
+#include <string.h>
+#include <sys/stat.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/ps.h>
+#include <unistd.h>
+#include <stdarg.h>
+#include <varargs.h>
+#include <limits.h>
+#include <_Nascii.h>
+#include <fcntl.h>
+#include <libgen.h>
+#include <termios.h>
+#include <zos.h>
+#include "EXTERN.h"
+#include "perl.h"
+#include "XSUB.h"
+
+void
+zos_copytags_fd(pTHX_ CV *cv)
+{
+  dXSARGS;
+  int ret = 0;
+
+  if (items != 2)
+    Perl_croak(aTHX_ "Usage: ZOS::Filespec::copytags_fd(f1, f2])");
+
+  int from_fd = (int)SvIV(ST(0));
+  int to_fd = (int)SvIV(ST(1));
+
+  char path[_XOPEN_PATH_MAX] = {0};
+  int rc = w_ioctl(from_fd, _IOCC_GPN, _XOPEN_PATH_MAX, path);
+  if (rc == 0) {
+    __e2a_l(path, _XOPEN_PATH_MAX);
+  }
+
+  struct stat src_statsbuf;
+  if (stat(path, &src_statsbuf)) {
+    ret = -1;
+  }
+  if (ret != -1) {
+    ret = __setfdccsid(to_fd,  (src_statsbuf.st_tag.ft_txtflag << 16) | src_statsbuf.st_tag.ft_ccsid);
+  }
+
+  XSRETURN_IV(ret);
+}
+
+void
+init_os_extras(void)
+{
+  dTHX;
+  char* file = __FILE__;
+
+  newXSproto("ZOS::Filespec::copytags_fd",zos_copytags_fd,file,"$;$");
+
+  return;
+}