p4raw-id: //depot/perl@17491
PerlIO operations on the original PerlIO *.
You should not call C<fclose()> on the file unless you call
C<PerlIO_releaseFILE()> to disassociate it from the PerlIO *.
-(And do not use PerlIO_importFILE() for doing to disassociation.)
+(Do not use PerlIO_importFILE() for doing the disassociation.)
Calling this function repeatedly will create a FILE * on each call
(and will push an :stdio layer each time as well).