Firefox won't start, fresh build and installation

["Thomas Mueller" <mueller6725%twc.com@localhost>]

Now I have a freshly built and installed Firefox on NetBSD 9.99.82-amd64, but it won't start. 

Is there s special way to start it, other than simply "firefox" from an X (icewm14) command prompt?

I get 

[Parent 4530, Main Thread] WARNING: failed to open shm: Not supported: file /pkgsrc/www/firefox/work10.amd64/firefox-88.0.1/ipc/chromium/src/base/shared_memory_posix.cc:354
[1]   Segmentation fault      /usr/pkg/lib/firefox/firefox "${@}"

I did "make clean clean-depends" so I no longer have /pkgsrc/www/firefox/work10.amd64 .

Earlier, I was successful building www/seamonkey, that runs.  Profile and session seem to migrate from my FreeBSD installation of Seamonkey.

I mamaged to install a considerable amount of software from pkgsrc on this computer; not so good on other computer where devel/libuv fails because it can't find or create ltmain.sh .

Tom