use xstrdup, not strdup in ll-merge.c
use xstrdup, not strdup in ll-merge.c

Otherwise, a fluky allocation failure would cause merge
configuration settings to be silently ignored.

Signed-off-by: Jim Meyering <15b0b14300fba1cff8c70eb2a5c1720ef2a4c654@redhat.com>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git