http://bugs.gentoo.org/301116

tweaked a little to avoid regenerating autotools

2009-07-29  Ralf Wildenhues  <Ralf.Wildenhues <at> gmx.de>

	* configure.in: Check for sys/user.h and linux/binfmts.h
	headers.
	* job.c: Include them if available.
	(construct_command_argv_internal): When constructing the command
	line with 'sh -c', use multiple arguments together with eval
	expansion to evade the Linux per-argument length limit
	MAX_ARG_STRLEN if it is defined.
	Problem reported against Automake by Xan Lopez <xan <at> gnome.org>.

--- job.c.orig	2010-01-15 18:36:53.000000000 +0200
+++ job.c	2010-01-15 18:41:09.000000000 +0200
@@ -29,6 +29,15 @@
 
 #include <string.h>
 
+#if defined(__linux__) /* defined (HAVE_LINUX_BINFMTS_H) && defined (HAVE_SYS_USER_H) */
+#include <sys/user.h>
+#include <unistd.h>
+#ifndef PAGE_SIZE
+#define PAGE_SIZE sysconf(_SC_PAGE_SIZE)
+#endif
+#include <linux/binfmts.h>
+#endif
+
 /* Default shell to use.  */
 #ifdef WINDOWS32
 #include <windows.h>
@@ -2697,9 +2702,19 @@
 #endif
     unsigned int line_len = strlen (line);
 
+#ifdef MAX_ARG_STRLEN
+    static char eval_line[] = "eval\\ \\\"set\\ x\\;\\ shift\\;\\ ";
+#define ARG_NUMBER_DIGITS 5
+#define EVAL_LEN (sizeof(eval_line)-1 + shell_len + 4 \
+                 + (7 + ARG_NUMBER_DIGITS) * 2 * line_len / (MAX_ARG_STRLEN - 2))
+#else
+#define EVAL_LEN 0
+#endif
     char *new_line = (char *) alloca (shell_len + (sizeof (minus_c) - 1)
-				      + (line_len * 2) + 1);
+				      + (line_len*2) + 1 + EVAL_LEN);
+
     char *command_ptr = NULL; /* used for batch_mode_shell mode */
+    char *args_ptr;
 
 # ifdef __EMX__ /* is this necessary? */
     if (!unixy_shell)
@@ -2712,6 +2727,30 @@
     bcopy (minus_c, ap, sizeof (minus_c) - 1);
     ap += sizeof (minus_c) - 1;
     command_ptr = ap;
+
+#if !defined (WINDOWS32) && defined (MAX_ARG_STRLEN)
+    if (unixy_shell && line_len > MAX_ARG_STRLEN)
+      {
+	unsigned j;
+	memcpy (ap, eval_line, sizeof (eval_line) - 1);
+	ap += sizeof (eval_line) - 1;
+	for (j = 1; j <= 2 * line_len / (MAX_ARG_STRLEN - 2); j++)
+	  ap += sprintf (ap, "\\$\\{%u\\}", j);
+	*ap++ = '\\';
+	*ap++ = '"';
+	*ap++ = ' ';
+	/* Copy only the first word of SHELL to $0.  */
+	for (p = shell; *p != '\0'; ++p)
+	  {
+	    if (isspace ((unsigned char)*p))
+	      break;
+	    *ap++ = *p;
+	  }
+	*ap++ = ' ';
+      }
+#endif
+    args_ptr = ap;
+
     for (p = line; *p != '\0'; ++p)
       {
 	if (restp != NULL && *p == '\n')
@@ -2760,6 +2799,14 @@
           }
 #endif
 	*ap++ = *p;
+
+#if !defined (WINDOWS32) && defined (MAX_ARG_STRLEN)
+	if (unixy_shell && line_len > MAX_ARG_STRLEN && (ap - args_ptr > MAX_ARG_STRLEN - 2))
+	  {
+	    *ap++ = ' ';
+	    args_ptr = ap;
+	  }
+#endif
       }
     if (ap == new_line + shell_len + sizeof (minus_c) - 1)
       /* Line was empty.  */