Integrate change #12703 from maintperl;

typemap stuff intervenes before declaration, move it to PREINIT
section

(an empty integrate, but now the files are in sync
 between the branches)

p4raw-link: @12703 on //depot/maint-5.6/perl: 88cc773e1e8562e40e686f6b5e5dac09c8147ef9

p4raw-id: //depot/perl@12705
p4raw-integrated: from //depot/maint-5.6/perl@12704 'ignore'
	ext/ODBM_File/ODBM_File.xs (@12668..)