- This only applies to scripts executed by the _internal_ shell script
interpreter.
- This patch reworks the log to look more like a shell transcript, and be less
verbose (but in the interest of calling attention to the important parts).
Here is an example of the new format, for commands with/without failures and
with/without output:
```
$ true
$ echo hi
hi
$ false
note: command had no output on stdout or stderr
error: command failed with exit status 1
```
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@271610 91177308-0d34-0410-b5e6-96231b3b80d8
