[Ecls-list] Infinite recursion if ecl_process_env fails

[Tobias C. Rittweiler]

In case `pthread_getspecific' fails in `ecl_process_env', the function
`FElibc_error' is invoked which internally conses which involves
`ecl_alloc_object' which again invokes `ecl_process_env', which fails
again and so on.

  -T.