coredump: default CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS=y

The userland ELF tools have been coping with partial-segments core files
for a few years now.  Multiple distro builds are now setting this option.
It behooves everyone who ever deals with core files to have more info
dumped in there, especially as more and more people's compilers are
producing build IDs.  Make it the default.

Anyone using older tools confused by these core files can configure this
option off, or just change /proc/PID/coredump_filter after boot.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/Kconfig.binfmt

@@ -42,7 +42,7 @@ config BINFMT_ELF_FDPIC
 
 config CORE_DUMP_DEFAULT_ELF_HEADERS
 	bool "Write ELF core dumps with partial segments"
-	default n
+	default y
 	depends on BINFMT_ELF && ELF_CORE
 	help
 	  ELF core dump files describe each memory mapping of the crashed
@@ -60,7 +60,7 @@ config CORE_DUMP_DEFAULT_ELF_HEADERS
 	  inherited.  See Documentation/filesystems/proc.txt for details.
 
 	  This config option changes the default setting of coredump_filter
-	  seen at boot time.  If unsure, say N.
+	  seen at boot time.  If unsure, say Y.
 
 config BINFMT_FLAT
 	bool "Kernel support for flat binaries"