fix --exit-code issues #1142 and #1139

[ryo1kato]

• Set default error code to -4 in main(), Fixes jq -e always returns 0 for empty input #1142
• fix --exit-code with more than one object in input, Fixes jq -e returns 4 for non-empty output with select() #1139
  • Return code 1 or 4 based on last output, not last input.

This is a rebase of PR #1140 to the latest master.

[coveralls]

Coverage decreased (-0.4%) to 84.588% when pulling 949e1ce on ryo1kato:fix-exit-code2-cherry into 90bc29c on stedolan:master.

[dongcarl]

Are there any updates on this? Would love for it to be merged as it's very much needed when using jq in shell scripts.

[nicowilliams]

Thanks!

[DrStrangepork]

This merge did not fix the problem in #1142

# echo | jq -e .; echo $?
0

[xiruizhao]

This merge did not fix the problem in #1142

# echo | jq -e .; echo $?
0

because this commit is merged after the jq 1.6 release. Hopefully the maintainer will release a new version soon.