Re: 'set -u' and $SHELL in makefiles [was: GNU M4]

[Eric Blake]

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According to Chan, Lawson on 1/30/2008 3:26 PM:
| Hi Eric,
|
| 1)  actually, I use the following commands to start the execution.  So I
am in the bash shell.
|     Bash
|     ./configure
|     make
|     Even though I am in the bash shell, running the 'env | grep SHELL'
gives SHELL=/usr/bin/ksh

Makes sense - bash doesn't overwrite SHELL if it was already set when bash
started.  But there's no need to start bash before running ./configure; it
should run just fine from ksh (or even the hideous Solaris 8 /bin/sh),
since the first part of ./configure is all about discovering a decent
shell if the current shell was not good enough.

| 2)  $echo $- returns bhimCBH
| 3)  I normally don't run set -u.  I still don't know why it is set
initially.

It's not.  Since $- doesn't contain u, 'set -u' is not active.

| 4)  I run ./configure in a fresh location and it behaves the same.
| 5)  The output of 'grep SHELL Makefile config.log' is attached in this
email.

And it shows merely "SHELL = /bin/bash".  No hint of -u, but configure did
decide that /bin/bash was a better choice than /bin/sh.

| 6)  I am using make 3.81.

Obviously GNU make, and not Solaris' version.  GNU make doesn't add -u, so
I'm a bit stumped.

|
| What about in a temporary directory (and use TAB for indenting):
|
| $ cat <<\EOF > Makefile
| all:
|         echo - $(SHELL) - $(MAKE) - $(MAKEFLAGS) - $$MAKEFLAGS - EOF $ make
|
| Then repeat, but with adding the same 'SHELL = ...' line at the
beginning that was in m4/Makefile?

You didn't run this test.

Also, could there be some other environment variables interfering?  At
this point, the output of 'env' might prove helpful.  Anyone else have ideas?

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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