get "run-program" output stream to string error on windows

[awlygj]

* (with-output-to-string (s) (run-program "c:\\windows\\system32\\cmd.exe" '("/c" "echo" "批处理文件") :output s))

debugger invoked on a TYPE-ERROR @1000AC7987 in thread
#<THREAD tid=4496 "main thread" RUNNING {1100BD8003}>:
  The value
    -26
  is not of type
    (UNSIGNED-BYTE 8)
  when setting an element of (ARRAY (UNSIGNED-BYTE 8))

Type HELP for debugger help, or (SB-EXT:EXIT) to exit from SBCL.

restarts (invokable by number or by possibly-abbreviated name):
  0: [ABORT] Exit debugger, returning to top level.

((LABELS SB-WIN32::COPY :IN SB-WIN32::WIN32-PROCESS-WAIT) #S(SB-WIN32::IO-COPIER :PIPE 588 :STREAM #<SB-IMPL::STRING-OUTPUT-STREAM {5FF3E3}> :EXTERNAL-FORMAT :DEFAULT :BUFFER #<SB-ALIEN-INTERNALS:ALIEN-VALUE :SAP #X01036DF0 :TYPE (* (SB-ALIEN:SIGNED 8))> :EVENT 576 :OVERLAPPED #<SB-ALIEN-INTERNALS:ALIEN-VALUE :SAP #X01031730 :TYPE (* (SB-ALIEN:STRUCT SB-WIN32::OVERLAPPED (SB-WIN32::INTERNAL (* #) :OFFSET 0) (SB-WIN32::INTERNAL-HIGH (* #) :OFFSET 64) (SB-WIN32::OFFSET (SB-ALIEN:UNSIGNED 32) :OFFSET 128) (SB-WIN32::OFFSET-HIGH (SB-ALIEN:UNSIGNED 32) :OFFSET 160) (SB-WIN32::EVENT (SB-ALIEN:SIGNED 64) :OFFSET 192)))>))
0] 0

chcp is 936.

SBCL 2.5.4