(sys::program-name) is broken on amd64 with pthreads

[Sam S. <sd...@gn...>]

Hi
(sys::program-name) returns garbage on amd64 with pthreads.
find_executable works and sets executable_name correctly, but when 
(sys::program-name) is called, executable_name contains garbage:

(gdb) run
Starting program: /homedata/ssteingold/src/clisp/current/build-g-mt/lisp.run -B 
. -N locale -E 1:1 -q -norc -M lispinit.mem
[Thread debugging using libthread_db enabled]
[New Thread 46912498368544 (LWP 23469)]
[Switching to Thread 46912498368544 (LWP 23469)]

Breakpoint 6, find_executable (
     program_name=0x7fff05cb8110 
"/homedata/ssteingold/src/clisp/current/build-g-mt/lisp.run") at execname.c:63
63        if (executable_name != NULL) return 0;
(gdb) finish
Run till exit from #0  find_executable (
     program_name=0x7fff05cb8110 
"/homedata/ssteingold/src/clisp/current/build-g-mt/lisp.run") at execname.c:63
init_lowest_level (argv=0x7fff05cb79a8) at ../src/spvw.d:2308
2308    }
Value returned is $1 = 0
(gdb) p executable_name
$2 = 0x1b016530 "/homedata/ssteingold/src/clisp/current/build-g-mt/lisp.run"
(gdb) c
Continuing.
STACK size: 98222 [0x2aaaaad90e00 0x2aaaaacd1090]
[New Thread 1090521408 (LWP 23474)]
[1]> (sys::program-name)
[Switching to Thread 1090521408 (LWP 23474)]

Breakpoint 7, get_executable_name () at execname.c:52
52      char *get_executable_name (void) { return executable_name; }
(gdb) p executable_name
$3 = 0x1b016530 "���"
(gdb) c
Continuing.
"���"
[2]>

observe that the memory location where executable_name points is the same, but 
the contents has been overwritten with garbage.

Sam