bug#10845: 24.0.93; Segfault in file locking

[Chong Yidong]

With latest trunk,

emacs -Q
M-: (push '("asdf" . ignore) file-name-handler-alist) RET
M-: (file-locked-p "asdf") RET

Program received signal SIGSEGV, Segmentation fault.
0x00000000005995f8 in Ffile_locked_p (filename=12761602) at filelock.c:691
691       MAKE_LOCK_NAME (lfname, filename);
(gdb) bt
#0  0x00000000005995f8 in Ffile_locked_p (filename=12761602) at filelock.c:691
#1  0x00000000006060e7 in eval_sub (form=18270774) at eval.c:2344
#2  0x0000000000605a9f in Feval (form=18270774, lexical=12761602)
    at eval.c:2198
#3  0x000000000060778a in Ffuncall (nargs=3, args=0x7fffffffcf00)
    at eval.c:2999
#4  0x0000000000653a58 in exec_byte_code (bytestr=10306257, vector=10306293, 
    maxdepth=20, args_template=12761602, nargs=0, args=0x0) at bytecode.c:785
...
Lisp Backtrace:
"file-locked-p" (0xffffccd0)
"eval" (0xffffcf08)
"eval-expression" (0xffffd3e8)
"call-interactively" (0xffffd7e8)


In GNU Emacs 24.0.93.13 (x86_64-unknown-linux-gnu, GTK+ Version 3.2.0)
 of 2012-02-19 on furball
Windowing system distributor `The X.Org Foundation', version 11.0.11004000
Configured using:
 `configure '--with-x-toolkit=gtk3' 'CFLAGS=-g''