By lowering debian/control's libgc-dev Build-Depends, Inkscape 0.45 successfully builds and runs under Dapper:
libgc-dev (>= 1:6.6-1)
** Also affects: dapper-backports (upstream)
Importance: Undecided
Status: Unconfirmed
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Please backport Inkscape 0.45 from Ubuntu Feisty
https://launchpad.net/bugs/83737