minor, soften clit_bits to also allow plain file descriptors and use them directly in diff_bits()

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, always call diff_bits() directly, with the out descriptor of the tool

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, don't evaluate stdout after the process has finished, instead redir pipes to our diff tool early

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, put all diff options into an array and use execvp()

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'core/buffd'

* core/buffd:
  minor, put all diff options into an array and use execvp()
  minor, don't evaluate stdout after the process has finished, instead redir pipes to our diff tool early
  minor, always call diff_bits() directly, with the out descriptor of the tool
  minor, soften clit_bits to also allow plain file descriptors and use them directly in diff_bits()
test, provide more regressions for tty mode

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>