Output contains trailing whitespace when run under nodejs

[rfk]

The fix committed in #2587 produces trailing whitespace in the program's output when run under nodejs:

$> cat test.c 
#include <stdio.h>
int main(void) {
  printf("hello world\n");
  return 0;
}
$> emcc -o test.js test.c
$> js test.js 
hello world
$> node test.js 
hello world

$>

This is probably OK most of the time, but it can cause problems if you need very precise output from the compiled program. For example, this is currently breaking my pypy.js build, because pypy configures itself by compiling test programs and parsing their output to learn various system details.

Can we make this workaround optional in some way? Is it still required on the very latest version of node, and if not can we disable it for versions where it's not needed?

[juj]

Hmm, indeed looking at the node.js issue tracker, the related issues are closed as fixed. I'll give this a look on Windows by building node from source, and see how it behaves.

Independent of that, we definitely can add some kind of conditional thing that allows skipping this behavior when it's considered harmful. Sorry for causing a regression for you here!

[kripken]

I'm not sure if it's needed on latest node or not. Anyhow, I added NODE_STDOUT_FLUSH_WORKAROUND to make this optional.

[juj]

The root problem does still occur in the latest node.js 0.10.31. I reported it fresh at nodejs/node-v0.x-archive#8329