$COMPILING
 $^C     The current value of the flag associated with the -c switch.
         Mainly of use with -MO=... to allow code to alter its behavior
         when being compiled, such as for example to AUTOLOAD at compile
         time rather than normal, deferred loading.  See perlcc.  Set-
         ting "$^C = 1" is similar to calling "B::minus_c".