[sbase] Fix buffer overflow in find.

It looks like the parse() function injects "-print"/"-a" arguments after
tokenizing, without resizing the "stack" variable.

TEST: running `find /bin` under asan does not crash.
Change-Id: I9533d787a22dce20216c57ce946b2faf89889fd8
diff --git a/find.c b/find.c
index cd2c7a5..2c9d78c 100644
--- a/find.c
+++ b/find.c
@@ -873,6 +873,7 @@
 		*out++ = (struct tok){ .u.pinfo = find_primary("-print"), .type = PRIM };
 	if (gflags.print == 2)
 		*out++ = and;
+	stack = ereallocarray(stack, argc + gflags.print, sizeof(*stack));
 
 	out->type = END;