5.004_56 threaded and "CONFIG key 'exe_ext' does not exist in Config.pm"

5.004_56 threaded and "CONFIG key 'exe_ext' does not exist in Config.pm"
To: perl5-porters@perl.org

It turns out that the potential for the "CONFIG key 'exe_ext'
does not exist in Config.pm" problem has been around for a while,
in the definition of SvTRUE().  It's just that non-gcc compilers
are more or less being built as CRIPPLED_CC when USE_THREADS is
defined (even if they can inline things).  The inline macro for
SvTRUE works with tied hashes and the EXISTS method, and the
functional version (sv_true in 5.004_56, or SvTRUE in 5.004_04)
does not, because it adds an excess mg_get() which replaces the
EXISTS result with a FETCH result.

p4raw-id: //depot/ansiperl@429