new file mode 100644
--- /dev/null
+++ b/lib/csharpcomp.c
@@ -0,0 +1,528 @@
+/* Compile a C# program.
+   Copyright (C) 2003-2005 Free Software Foundation, Inc.
+   Written by Bruno Haible <bruno@clisp.org>, 2003.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software Foundation,
+   Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <alloca.h>
+
+/* Specification.  */
+#include "csharpcomp.h"
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "execute.h"
+#include "pipe.h"
+#include "wait-process.h"
+#include "getline.h"
+#include "sh-quote.h"
+#include "safe-read.h"
+#include "xallocsa.h"
+#include "error.h"
+#include "gettext.h"
+
+#define _(str) gettext (str)
+
+
+/* Survey of C# compilers.
+
+   Program    from
+
+   cscc       pnet
+   mcs        mono
+   csc        sscli
+
+   We try the CIL interpreters in the following order:
+     1. "cscc", because it is a completely free system.
+     2. "mcs", because it is a free system but doesn't integrate so well
+        with Unix. (Command line options start with / instead of -. Errors go
+        to stdout instead of stderr. Source references are printed as
+        "file(lineno)" instead of "file:lineno:".)
+     3. "csc", although it is not free, because it is a kind of "reference
+        implementation" of C#.
+   But the order can be changed through the --enable-csharp configuration
+   option.
+ */
+
+static int
+compile_csharp_using_pnet (const char * const *sources,
+			   unsigned int sources_count,
+			   const char * const *libdirs,
+			   unsigned int libdirs_count,
+			   const char * const *libraries,
+			   unsigned int libraries_count,
+			   const char *output_file, bool output_is_library,
+			   bool optimize, bool debug,
+			   bool verbose)
+{
+  static bool cscc_tested;
+  static bool cscc_present;
+
+  if (!cscc_tested)
+    {
+      /* Test for presence of cscc:
+	 "cscc --version >/dev/null 2>/dev/null"  */
+      char *argv[3];
+      int exitstatus;
+
+      argv[0] = "cscc";
+      argv[1] = "--version";
+      argv[2] = NULL;
+      exitstatus = execute ("cscc", "cscc", argv, false, false, true, true,
+			    true, false);
+      cscc_present = (exitstatus == 0);
+      cscc_tested = true;
+    }
+
+  if (cscc_present)
+    {
+      unsigned int argc;
+      char **argv;
+      char **argp;
+      int exitstatus;
+      unsigned int i;
+
+      argc =
+	1 + (output_is_library ? 1 : 0) + 2 + 2 * libdirs_count
+	+ 2 * libraries_count + (optimize ? 1 : 0) + (debug ? 1 : 0)
+	+ sources_count;
+      argv = (char **) xallocsa ((argc + 1) * sizeof (char *));
+
+      argp = argv;
+      *argp++ = "cscc";
+      if (output_is_library)
+	*argp++ = "-shared";
+      *argp++ = "-o";
+      *argp++ = (char *) output_file;
+      for (i = 0; i < libdirs_count; i++)
+	{
+	  *argp++ = "-L";
+	  *argp++ = (char *) libdirs[i];
+	}
+      for (i = 0; i < libraries_count; i++)
+	{
+	  *argp++ = "-l";
+	  *argp++ = (char *) libraries[i];
+	}
+      if (optimize)
+	*argp++ = "-O";
+      if (debug)
+	*argp++ = "-g";
+      for (i = 0; i < sources_count; i++)
+	{
+	  const char *source_file = sources[i];
+	  if (strlen (source_file) >= 9
+	      && memcmp (source_file + strlen (source_file) - 9, ".resource",
+			 9) == 0)
+	    {
+	      char *option = (char *) xallocsa (12 + strlen (source_file) + 1);
+
+	      memcpy (option, "-fresources=", 12);
+	      strcpy (option + 12, source_file);
+	      *argp++ = option;
+	    }
+	  else
+	    *argp++ = (char *) source_file;
+	}
+      *argp = NULL;
+      /* Ensure argv length was correctly calculated.  */
+      if (argp - argv != argc)
+	abort ();
+
+      if (verbose)
+	{
+	  char *command = shell_quote_argv (argv);
+	  printf ("%s\n", command);
+	  free (command);
+	}
+
+      exitstatus = execute ("cscc", "cscc", argv, false, false, false, false,
+			    true, true);
+
+      for (i = 0; i < sources_count; i++)
+	if (argv[argc - sources_count + i] != sources[i])
+	  freesa (argv[argc - sources_count + i]);
+      freesa (argv);
+
+      return (exitstatus != 0);
+    }
+  else
+    return -1;
+}
+
+static int
+compile_csharp_using_mono (const char * const *sources,
+			   unsigned int sources_count,
+			   const char * const *libdirs,
+			   unsigned int libdirs_count,
+			   const char * const *libraries,
+			   unsigned int libraries_count,
+			   const char *output_file, bool output_is_library,
+			   bool optimize, bool debug,
+			   bool verbose)
+{
+  static bool mcs_tested;
+  static bool mcs_present;
+
+  if (!mcs_tested)
+    {
+      /* Test for presence of mcs:
+	 "mcs --version >/dev/null 2>/dev/null"  */
+      char *argv[3];
+      int exitstatus;
+
+      argv[0] = "mcs";
+      argv[1] = "--version";
+      argv[2] = NULL;
+      exitstatus = execute ("mcs", "mcs", argv, false, false, true, true, true,
+			    false);
+      mcs_present = (exitstatus == 0);
+      mcs_tested = true;
+    }
+
+  if (mcs_present)
+    {
+      unsigned int argc;
+      char **argv;
+      char **argp;
+      pid_t child;
+      int fd[1];
+      FILE *fp;
+      char *line[2];
+      size_t linesize[2];
+      size_t linelen[2];
+      unsigned int l;
+      int exitstatus;
+      unsigned int i;
+
+      argc =
+	1 + (output_is_library ? 1 : 0) + 2 + 2 * libdirs_count
+	+ 2 * libraries_count + (debug ? 1 : 0) + sources_count;
+      argv = (char **) xallocsa ((argc + 1) * sizeof (char *));
+
+      argp = argv;
+      *argp++ = "mcs";
+      if (output_is_library)
+	*argp++ = "-target:library";
+      *argp++ = "-o";
+      *argp++ = (char *) output_file;
+      for (i = 0; i < libdirs_count; i++)
+	{
+	  *argp++ = "-L";
+	  *argp++ = (char *) libdirs[i];
+	}
+      for (i = 0; i < libraries_count; i++)
+	{
+	  *argp++ = "-r";
+	  *argp++ = (char *) libraries[i];
+	}
+      if (debug)
+	*argp++ = "-g";
+      for (i = 0; i < sources_count; i++)
+	{
+	  const char *source_file = sources[i];
+	  if (strlen (source_file) >= 9
+	      && memcmp (source_file + strlen (source_file) - 9, ".resource",
+			 9) == 0)
+	    {
+	      char *option = (char *) xallocsa (10 + strlen (source_file) + 1);
+
+	      memcpy (option, "-resource:", 10);
+	      strcpy (option + 10, source_file);
+	      *argp++ = option;
+	    }
+	  else
+	    *argp++ = (char *) source_file;
+	}
+      *argp = NULL;
+      /* Ensure argv length was correctly calculated.  */
+      if (argp - argv != argc)
+	abort ();
+
+      if (verbose)
+	{
+	  char *command = shell_quote_argv (argv);
+	  printf ("%s\n", command);
+	  free (command);
+	}
+
+      child = create_pipe_in ("mcs", "mcs", argv, NULL, false, true, true, fd);
+
+      /* Read the subprocess output, copying it to stderr.  Drop the last
+	 line if it starts with "Compilation succeeded".  */
+      fp = fdopen (fd[0], "r");
+      if (fp == NULL)
+	error (EXIT_FAILURE, errno, _("fdopen() failed"));
+      line[0] = NULL; linesize[0] = 0;
+      line[1] = NULL; linesize[1] = 0;
+      l = 0;
+      for (;;)
+	{
+	  linelen[l] = getline (&line[l], &linesize[l], fp);
+	  if (linelen[l] == (size_t)(-1))
+	    break;
+	  l = (l + 1) % 2;
+	  if (line[l] != NULL)
+	    fwrite (line[l], 1, linelen[l], stderr);
+	}
+      l = (l + 1) % 2;
+      if (line[l] != NULL
+	  && !(linelen[l] >= 21
+	       && memcmp (line[l], "Compilation succeeded", 21) == 0))
+	fwrite (line[l], 1, linelen[l], stderr);
+      if (line[0] != NULL)
+	free (line[0]);
+      if (line[1] != NULL)
+	free (line[1]);
+      fclose (fp);
+
+      /* Remove zombie process from process list, and retrieve exit status.  */
+      exitstatus = wait_subprocess (child, "mcs", false, false, true, true);
+
+      for (i = 0; i < sources_count; i++)
+	if (argv[argc - sources_count + i] != sources[i])
+	  freesa (argv[argc - sources_count + i]);
+      freesa (argv);
+
+      return (exitstatus != 0);
+    }
+  else
+    return -1;
+}
+
+static int
+compile_csharp_using_sscli (const char * const *sources,
+			    unsigned int sources_count,
+			    const char * const *libdirs,
+			    unsigned int libdirs_count,
+			    const char * const *libraries,
+			    unsigned int libraries_count,
+			    const char *output_file, bool output_is_library,
+			    bool optimize, bool debug,
+			    bool verbose)
+{
+  static bool csc_tested;
+  static bool csc_present;
+
+  if (!csc_tested)
+    {
+      /* Test for presence of csc:
+	 "csc -help >/dev/null 2>/dev/null \
+	  && ! { csc -help 2>/dev/null | grep -i chicken > /dev/null; }"  */
+      char *argv[3];
+      pid_t child;
+      int fd[1];
+      int exitstatus;
+
+      argv[0] = "csc";
+      argv[1] = "-help";
+      argv[2] = NULL;
+      child = create_pipe_in ("csc", "csc", argv, DEV_NULL, true, true, false,
+			      fd);
+      csc_present = false;
+      if (child != -1)
+	{
+	  /* Read the subprocess output, and test whether it contains the
+	     string "chicken".  */
+	  char c[7];
+	  size_t count = 0;
+
+	  csc_present = true;
+	  while (safe_read (fd[0], &c[count], 1) > 0)
+	    {
+	      if (c[count] >= 'A' && c[count] <= 'Z')
+		c[count] += 'a' - 'A';
+	      count++;
+	      if (count == 7)
+		{
+		  if (memcmp (c, "chicken", 7) == 0)
+		    csc_present = false;
+		  c[0] = c[1]; c[1] = c[2]; c[2] = c[3];
+		  c[3] = c[4]; c[4] = c[5]; c[5] = c[6];
+		  count--;
+		}
+	    }
+
+	  close (fd[0]);
+
+	  /* Remove zombie process from process list, and retrieve exit
+	     status.  */
+	  exitstatus =
+	    wait_subprocess (child, "csc", false, true, true, false);
+	  if (exitstatus != 0)
+	    csc_present = false;
+	}
+      csc_tested = true;
+    }
+
+  if (csc_present)
+    {
+      unsigned int argc;
+      char **argv;
+      char **argp;
+      int exitstatus;
+      unsigned int i;
+
+      argc =
+	1 + 1 + 1 + libdirs_count + libraries_count
+	+ (optimize ? 1 : 0) + (debug ? 1 : 0) + sources_count;
+      argv = (char **) xallocsa ((argc + 1) * sizeof (char *));
+
+      argp = argv;
+      *argp++ = "csc";
+      *argp++ = (output_is_library ? "-target:library" : "-target:exe");
+      {
+	char *option = (char *) xallocsa (5 + strlen (output_file) + 1);
+	memcpy (option, "-out:", 5);
+	strcpy (option + 5, output_file);
+	*argp++ = option;
+      }
+      for (i = 0; i < libdirs_count; i++)
+	{
+	  char *option = (char *) xallocsa (5 + strlen (libdirs[i]) + 1);
+	  memcpy (option, "-lib:", 5);
+	  strcpy (option + 5, libdirs[i]);
+	  *argp++ = option;
+	}
+      for (i = 0; i < libraries_count; i++)
+	{
+	  char *option = (char *) xallocsa (11 + strlen (libraries[i]) + 1);
+	  memcpy (option, "-reference:", 11);
+	  strcpy (option + 11, libraries[i]);
+	  *argp++ = option;
+	}
+      if (optimize)
+	*argp++ = "-optimize+";
+      if (debug)
+	*argp++ = "-debug+";
+      for (i = 0; i < sources_count; i++)
+	{
+	  const char *source_file = sources[i];
+	  if (strlen (source_file) >= 9
+	      && memcmp (source_file + strlen (source_file) - 9, ".resource",
+			 9) == 0)
+	    {
+	      char *option = (char *) xallocsa (10 + strlen (source_file) + 1);
+
+	      memcpy (option, "-resource:", 10);
+	      strcpy (option + 10, source_file);
+	      *argp++ = option;
+	    }
+	  else
+	    *argp++ = (char *) source_file;
+	}
+      *argp = NULL;
+      /* Ensure argv length was correctly calculated.  */
+      if (argp - argv != argc)
+	abort ();
+
+      if (verbose)
+	{
+	  char *command = shell_quote_argv (argv);
+	  printf ("%s\n", command);
+	  free (command);
+	}
+
+      exitstatus = execute ("csc", "csc", argv, false, false, false, false,
+			    true, true);
+
+      for (i = 2; i < 3 + libdirs_count + libraries_count; i++)
+	freesa (argv[i]);
+      for (i = 0; i < sources_count; i++)
+	if (argv[argc - sources_count + i] != sources[i])
+	  freesa (argv[argc - sources_count + i]);
+      freesa (argv);
+
+      return (exitstatus != 0);
+    }
+  else
+    return -1;
+}
+
+bool
+compile_csharp_class (const char * const *sources,
+		      unsigned int sources_count,
+		      const char * const *libdirs,
+		      unsigned int libdirs_count,
+		      const char * const *libraries,
+		      unsigned int libraries_count,
+		      const char *output_file,
+		      bool optimize, bool debug,
+		      bool verbose)
+{
+  bool output_is_library =
+    (strlen (output_file) >= 4
+     && memcmp (output_file + strlen (output_file) - 4, ".dll", 4) == 0);
+  int result;
+
+  /* First try the C# implementation specified through --enable-csharp.  */
+#if CSHARP_CHOICE_PNET
+  result = compile_csharp_using_pnet (sources, sources_count,
+				      libdirs, libdirs_count,
+				      libraries, libraries_count,
+				      output_file, output_is_library,
+				      optimize, debug, verbose);
+  if (result >= 0)
+    return (bool) result;
+#endif
+
+#if CSHARP_CHOICE_MONO
+  result = compile_csharp_using_mono (sources, sources_count,
+				      libdirs, libdirs_count,
+				      libraries, libraries_count,
+				      output_file, output_is_library,
+				      optimize, debug, verbose);
+  if (result >= 0)
+    return (bool) result;
+#endif
+
+  /* Then try the remaining C# implementations in our standard order.  */
+#if !CSHARP_CHOICE_PNET
+  result = compile_csharp_using_pnet (sources, sources_count,
+				      libdirs, libdirs_count,
+				      libraries, libraries_count,
+				      output_file, output_is_library,
+				      optimize, debug, verbose);
+  if (result >= 0)
+    return (bool) result;
+#endif
+
+#if !CSHARP_CHOICE_MONO
+  result = compile_csharp_using_mono (sources, sources_count,
+				      libdirs, libdirs_count,
+				      libraries, libraries_count,
+				      output_file, output_is_library,
+				      optimize, debug, verbose);
+  if (result >= 0)
+    return (bool) result;
+#endif
+
+  result = compile_csharp_using_sscli (sources, sources_count,
+				       libdirs, libdirs_count,
+				       libraries, libraries_count,
+				       output_file, output_is_library,
+				       optimize, debug, verbose);
+  if (result >= 0)
+    return (bool) result;
+
+  error (0, 0, _("C# compiler not found, try installing pnet"));
+  return true;
+}