libcom_err: Fix file descriptor leak after an exec

Some applications repeatedly re-exec themselves, and if they use the
com_err library, they can leak a file descriptor for each re-exec.
Fix this by setting the close-on-exec flag on the debug file
descriptor.  In addition, if the COMERR_DEBUG environment variable
isn't set, don't open the file handle at all.

Addresses-Red-Hat-Bugzilla: #464689

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
1 file changed