[vile] duplicate free core dump with "set"

[Paul Fox]

vile 9.8m, x86-64

reproduce with:
    invoke vile (with or without a file arg, or a .vilerc)
    :set noundoable
    :set all

if built against glibc, vile will trap due to a "double free or
corruption":

        Program received signal SIGABRT, Aborted.
        0x00007ffff75f0425 in __GI_raise (sig=<optimized out>)
            at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
        64      ../nptl/sysdeps/unix/sysv/linux/raise.c: No such file or 
directory.
        (gdb) where
        #0  0x00007ffff75f0425 in __GI_raise (sig=<optimized out>)
            at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
        #1  0x00007ffff75f3b8b in __GI_abort () at abort.c:91
        #2  0x00007ffff762e39e in __libc_message (do_abort=2, 
            fmt=0x7ffff7738748 "*** glibc detected *** %s: %s: 0x%s ***\n")
            at ../sysdeps/unix/sysv/linux/libc_fatal.c:201
        #3  0x00007ffff7638b96 in malloc_printerr (action=3, 
            str=0x7ffff7738938 "double free or corruption (fasttop)", 
            ptr=<optimized out>) at malloc.c:5039
        #4  0x0000000000447777 in lfree (lp=0x708d60, bp=0x716ea0) at line.c:131
        #5  0x0000000000418127 in bclear (bp=0x716ea0) at buffer.c:2764
        #6  0x000000000045ca3d in liststuff (name=0x48d29a "[Settings]", 
appendit=0, 
            func=0x44de1a <makemodelist>, iarg=0, vargp=0x714b90) at 
random.c:142
        #7  0x000000000044f8de in listmodes (f=0, n=0) at modes.c:1431
        #8  0x00000000004506c6 in show_Settings (bp=0x716ea0) at modes.c:1766
        #9  0x000000000041d80f in recompute_buffer (bp=0x716ea0) at 
display.c:2137
        #10 0x0000000000422950 in update (force=0) at display.c:4233
        #11 0x0000000000406d20 in main_loop () at main.c:1124
        #12 0x0000000000406c1b in main (argc=3, argv=0x7fffffffe698) at 
main.c:1082
        (gdb) 
        #0  0x00007ffff75f0425 in __GI_raise (sig=<optimized out>)
            at ../nptl/sysdeps/unix/sysv/linux/raise.c:64
        #1  0x00007ffff75f3b8b in __GI_abort () at abort.c:91
        #2  0x00007ffff762e39e in __libc_message (do_abort=2, 
            fmt=0x7ffff7738748 "*** glibc detected *** %s: %s: 0x%s ***\n")
            at ../sysdeps/unix/sysv/linux/libc_fatal.c:201
        #3  0x00007ffff7638b96 in malloc_printerr (action=3, 
            str=0x7ffff7738938 "double free or corruption (fasttop)", 
            ptr=<optimized out>) at malloc.c:5039
        #4  0x0000000000447777 in lfree (lp=0x708d60, bp=0x716ea0) at line.c:131
        #5  0x0000000000418127 in bclear (bp=0x716ea0) at buffer.c:2764
        #6  0x000000000045ca3d in liststuff (name=0x48d29a "[Settings]", 
appendit=0, 
            func=0x44de1a <makemodelist>, iarg=0, vargp=0x714b90) at 
random.c:142
        #7  0x000000000044f8de in listmodes (f=0, n=0) at modes.c:1431
        #8  0x00000000004506c6 in show_Settings (bp=0x716ea0) at modes.c:1766
        #9  0x000000000041d80f in recompute_buffer (bp=0x716ea0) at 
display.c:2137
        #10 0x0000000000422950 in update (force=0) at display.c:4233
        #11 0x0000000000406d20 in main_loop () at main.c:1124
        #12 0x0000000000406c1b in main (argc=3, argv=0x7fffffffe698) at 
main.c:1082




----------------------
 paul fox, address@hidden (arlington, ma, where it's 64.0 degrees)