[PATCH 0/6 v3] Add execvp failure diagnostics

This patch series replaces $gmane/187026. It aims to improve the information provided after execvp fails in run-command.

This series takes a rather different approach than the previous one. In the former the focus was on determining what might cause an EACCES failure. This series focuses on trying to provide hints on what went wrong on any error.

The resulting checking produces behavior rather like bash, with the notable exception that we consider "Not found and PATH access issues" a failure, where bash doesn't.

[PATCH 1/5] t0061: Fix incorrect indentation [PATCH 2/5] t0061: Add tests [PATCH 3/5] run-command: Elaborate execvp error checking [PATCH 4/5] run-command: Warn if PATH entry cannot be searched [PATCH 5/5] run-command: Error out if interpreter not found

run-command.c | 140 +++++++++++++++++++++++++++++++++++++++++++++--- t/t0061-run-command.sh | 57 ++++++++++++++++++- 2 files changed, 186 insertions(+), 11 deletions(-)