setbrk: but don't wipe shrinks of the stack!

diff --git a/Applications/V7/cmd/sh/setbrk.c b/Applications/V7/cmd/sh/setbrk.c
index fe1b31a..14a58b0 100644 (file)
--- a/Applications/V7/cmd/sh/setbrk.c
+++ b/Applications/V7/cmd/sh/setbrk.c
@@ -16,7 +16,7 @@ void *setbrk(intptr_t incr)
 {
        uint8_t *a = sbrk(incr);
        brkend = a + incr;
-       if (a != (uint8_t *)-1)
+       if (a != (uint8_t *)-1 && incr > 0)
                memset(a, 0, incr);
        return a;
 }