Rewrite grub-install, grub-mkrescue, grub-mkstandalone and grub-mknetdir

the function of these files exceeds what can be sanely handled in shell
	in posix-comaptible way. Also writing it in C extends the functionality
	to non-UNIX-like OS and minimal environments.

grub-core/osdep/linux/platform.c

@@ -0,0 +1,85 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2013 Free Software Foundation, Inc.
+ *
+ *  GRUB 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 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB 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 GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+
+#include <grub/util/install.h>
+#include <grub/emu/exec.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <string.h>
+
+#include <sys/utsname.h>
+
+static int
+is_not_empty_directory (const char *dir)
+{
+  DIR *d;
+  struct dirent *de;
+
+  d = opendir (dir);
+  if (!d)
+    return 0;
+  while ((de = readdir (d)))
+    {
+      if (strcmp (de->d_name, ".") == 0
+	  || strcmp (de->d_name, "..") == 0)
+	continue;
+      closedir (d);
+      return 1;
+    }
+
+  closedir (d);
+  return 0;
+}
+
+static int
+is_64_kernel (void)
+{
+  struct utsname un;
+
+  if (uname (&un) < 0)
+    return 0;
+
+  return strcmp (un.machine, "x86_64") == 0;
+}
+
+const char *
+grub_install_get_default_x86_platform (void)
+{ 
+  /*
+     On Linux, we need the efivars kernel modules.
+     If no EFI is available this module just does nothing
+     besides a small hello and if we detect efi we'll load it
+     anyway later. So it should be safe to
+     try to load it here.
+   */
+  grub_util_exec ((const char * []){ "modprobe", "-q",
+	"efivars", NULL });
+  if (is_not_empty_directory ("/sys/firmware/efi"))
+    {
+      if (is_64_kernel ())
+	return "x86_64-efi";
+      else
+	return "i386-efi";
+    }
+  else if (is_not_empty_directory ("/proc/device-tree"))
+    return "i386-ieee1275";
+  else
+    return "i386-pc";
+}