libreoffice/coinmp binary packages broken

[nia <nia%NetBSD.org@localhost>]

when installing libreoffice on a fresh 9.0:

$ sudo pkgin install libreoffice
calculating dependencies...done.
/usr/lib/libstdc++.so.7, needed by gcc7-7.5.0nb2 is not present in this system.

101 packages to install:
[...]

1 to refresh, 0 to upgrade, 101 to install
648M to download, 2427M to install
the following packages have unmet requirements:   gcc7-7.5.0nb2

this appears to be caused by libreoffice's coinmp dependency:

$ sudo pkgin install coinmp
calculating dependencies...done.
/usr/lib/libstdc++.so.7, needed by gcc7-7.5.0nb2 is not present in this system.

2 packages to install:
  gsed-4.8 coinmp-1.8.4

0 to refresh, 0 to upgrade, 2 to install
62M to download, 309M to install
the following packages have unmet requirements:   gcc7-7.5.0nb2

I tried to fix this here:

https://github.com/NetBSD/pkgsrc/commit/744e276b8c49e1a3190f511c6d44d473a7d6b5eb

but have no idea if the fix is correct.

can someone more familiar take a look?

[first post appeared to get spam filtered, sorry if this is a duplicate