/* On Linux kernels 2.6.26-2.6.29, dup2 (fd, fd) returns -EBADF.
On Cygwin 1.5.x, dup2 (1, 1) returns 0.
On Cygwin 1.7.17, dup2 (1, -1) dumps core.
/* On Linux kernels 2.6.26-2.6.29, dup2 (fd, fd) returns -EBADF.
On Cygwin 1.5.x, dup2 (1, 1) returns 0.
On Cygwin 1.7.17, dup2 (1, -1) dumps core.