In Linux? No, C/C++-compiled binaries with dynamic linking often had issues due to glibc versions diffing,etc but you could always compiled things statically.
"not ok" by LGPL licence so an issue for games,etc that wanted closed source so people talked about it, but a malicious worm creator could definitely go there since they probably wouldn't care about (L)GPL compliance (remember Linus has always been very hard on patches not breaking userspace ABI's).
Yeah. Emphasis on the "seem" part. A false sense of security brought on by, "If binary artifacts for package _foo_ can't be ported between distros, what chance do worms have?" plus the even older memory that the Morris worm had been designed around (and limited to) certain target platforms and architectures: https://en.wikipedia.org/wiki/Morris_worm
"not ok" by LGPL licence so an issue for games,etc that wanted closed source so people talked about it, but a malicious worm creator could definitely go there since they probably wouldn't care about (L)GPL compliance (remember Linus has always been very hard on patches not breaking userspace ABI's).