darwin: reduce fsevents thread stack size
darwin: reduce fsevents thread stack size

The fsevents watcher thread only needs a minimal amount of stack space
in order to run. Restrict its stack size so there's more address space
left for the libuv user.

unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso,unknownbrackets/maxcso