[krbdev.mit.edu #5442] memory leak in gss_accept_sec_context()

[Tom Yu via RT]

Having a goto label named "exit" is not robust.  While technically the C
standard only reserves library header-declared file scope identifiers at
file scope, and goto labels are not at file scope, it is still a bad
idea to name a goto label "exit".  Operating systems sometimes use
object-like macros to implement symbol renaming, even though that
practice is not formally permitted by the standard.