Merge branch 'js/run-command-updates'

* js/run-command-updates: api-run-command.txt: describe error behavior of run_command functions run-command.c: squelch a "use before assignment" warning receive-pack: remove unnecessary run_status report run_command: report failure to execute the program, but optionally don't run_command: encode deadly signal number in the return value run_command: report system call errors instead of returning error codes run_command: return exit code as positive value MinGW: simplify waitpid() emulation macros