The maximum command line size allowed by the Linux kernel used to be 128kB. This might sound crazy, but that limit was a real constraint for some Google services. My guess is that this is referring to a kernel patch to increase the maximum size.

This is a somewhat educated guess. A long time ago at Google I used to work on the program that was used to launch most jobs on the clusters. To help mitigate the command line length problems, the launcher preferred generating command lines with -nofoo instead of --foo=false, and -foo instead of -foo=true. This saved a few characters per boolean flag. Of course it also caused no end of trouble for people who'd defined their own "three-state boolean" flags that could e.g. be true/false/autodetect. Not the finest hour of engineering, in retrospect.

Shouldn't programs simply support a @args.txt argument which references a file containing more arguments to the program? Most build tools I've seen do that and it makes command-line length limits mostly a moot point.