http://bugs.gentoo.org/221281
temacs segfaults in dump-emacs under Linux 2.6.25
Patch backported from Emacs 22 and upstream bug 900.
It comprises parts of the following changes:

2008-10-21  Jan Djärv  <jan.h.d@swipnet.se>

	* emacs.c (main): Unconditionally set PER_LINUX32 and exec
	temacs when dumping if HAVE_PERSONALITY_LINUX32 is defined

2005-07-01  Masatake YAMATO  <jet@gyve.org>

	* emacs.c (main): Passing ADD_NO_RANDOMIZE to `personality'.

2004-10-20  Jan Djärv  <jan.h.d@swipnet.se>

	* configure.in (HAVE_PERSONALITY_LINUX32): New test if PER_LINUX32
	can be set.

--- emacs-21.4-orig/configure.in	2008-05-11 00:02:58.000000000 +0200
+++ emacs-21.4/configure.in	2008-05-11 00:29:23.000000000 +0200
@@ -1358,6 +1358,18 @@
 AC_CHECK_HEADERS(sys/select.h sys/timeb.h sys/time.h unistd.h utime.h \
   linux/version.h sys/systeminfo.h termios.h limits.h string.h stdlib.h \
   termcap.h stdio_ext.h fcntl.h term.h strings.h)
+
+AC_MSG_CHECKING(if personality LINUX32 can be set)
+AC_TRY_COMPILE([#include <sys/personality.h>], [personality (PER_LINUX32)],
+	       emacs_cv_personality_linux32=yes,
+	       emacs_cv_personality_linux32=no)
+AC_MSG_RESULT($emacs_cv_personality_linux32)
+
+if test $emacs_cv_personality_linux32 = yes; then
+  AC_DEFINE(HAVE_PERSONALITY_LINUX32, 1,
+	    [Define to 1 if personality LINUX32 can be set.])
+fi
+
 AC_HEADER_STDC
 AC_HEADER_TIME
 AC_DECL_SYS_SIGLIST
--- emacs-21.4-orig/src/config.in	2002-07-09 00:23:31.000000000 +0200
+++ emacs-21.4/src/config.in	2008-05-11 00:13:38.000000000 +0200
@@ -183,6 +183,7 @@
 #undef HAVE_UALARM
 #undef HAVE_SYS_WAIT_H
 #undef HAVE_STRINGS_H
+#undef HAVE_PERSONALITY_LINUX32
 
 #undef HAVE_LIBDNET
 #undef HAVE_LIBPTHREADS
--- emacs-21.4-orig/src/emacs.c	2002-08-29 21:27:07.000000000 +0200
+++ emacs-21.4/src/emacs.c	2008-05-11 00:26:38.000000000 +0200
@@ -61,6 +61,13 @@
 #include <sys/resource.h>
 #endif
 
+#ifdef HAVE_PERSONALITY_LINUX32
+#include <sys/personality.h>
+#ifndef ADDR_NO_RANDOMIZE
+#define ADDR_NO_RANDOMIZE 0x0040000
+#endif
+#endif
+
 #ifndef O_RDWR
 #define O_RDWR 2
 #endif
@@ -763,6 +770,28 @@
 	}
     }
 
+#ifdef HAVE_PERSONALITY_LINUX32
+  /* See if there is a gap between the end of BSS and the heap.
+     In that case, set personality and exec ourself again.  */
+  if (!initialized
+      && (strcmp (argv[argc-1], "dump") == 0
+	  || strcmp (argv[argc-1], "bootstrap") == 0)
+      && !getenv ("EMACS_HEAP_EXEC"))
+    {
+      /* Set this so we only do this once.  */
+      putenv ("EMACS_HEAP_EXEC=true");
+
+      /* A flag to turn off address randomization which is introduced
+	 in linux kernel shipped with fedora core 4 */
+      personality (PER_LINUX32 | ADDR_NO_RANDOMIZE);
+
+      execvp (argv[0], argv);
+
+      /* If the exec fails, try to dump anyway.  */
+      perror ("execvp");
+    }
+#endif /* HAVE_PERSONALITY_LINUX32 */
+
 /* Map in shared memory, if we are using that.  */
 #ifdef HAVE_SHM
   if (argmatch (argv, argc, "-nl", "--no-shared-memory", 6, NULL, &skip_args))