Gentoo/Inkscape/Gcc/…… bleh

So I emerged Inkscape 0.43 after working perfectly fine for a while with version 0.41, after the process finished succesfully, I run inkscape and I see this message:

*** glibc detected *** double free or corruption (out):
0x08847df0 ***

Emergency save activated!
Emergency save completed. Inkscape will close now.
If you can reproduce this crash, please file a bug at
www.inkscape.org
with a detailed description of the steps leading to the
crash, so we can fix it.

I check sourceforge bug tracker system and look for a similar bug, and I found this one.

At the same time, I /joined #inkscape channel and asked about it, and I got this response.

[15:00] < ^-> [mental] inkscape wasn't compiled with the same gcc version as the C++ libraries you linked it against
[15:00] < ^-> [mental] occupational hazard of using a source-based distro like Gentoo
[15:00] < ^-> [ACSpike] Jj: C++ ABI mismatch means you need to recompile all the deps with the same  compiler
[15:00] < ^-> [ishmal2] true,  emerging source?
[15:05] < ^-> [ishmal2] part of the problem was not just the c++ libs changing, but even g++ changed abi a couple of times in the 3.x series,  without incrementing the version #

Which is good cause they both told me the same thing, I reemerged libgtkmm, libsigc++ and scim, with my new gcc version (I compiled all of that including my old Inkscape with 3.3 and now I have 3.4). And then Inkscape started

Now I have that message showing up when I try to open the font dialog, any idea which library do I need to recompile in order to fix that?

At least Gentoo is doing its labor making me learn stuff