Add bazel-build-bazel-command

[jlisee]

Sometimes users have custom invocation scripts that eliminate the need
for a user to install bazel to build their project. This allow
bazel-build to use that invocation script directly.

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[jlisee]

@googlebot I signed it!

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[phst]

Nit: Quote Lisp symbols in docstrings `like-this' or ‘like-this’. See https://www.gnu.org/software/emacs/manual/html_node/elisp/Documentation-Tips.html.

[jlisee]

Thanks, new to this part of elisp will fix this in a bit.

[phst]

SG, thanks, please ping this thread once you're ready.

[tautomaton]

Laurent, is this ready to merge?

[laurentlb]

The last reviewer comment was:

SG, thanks, please ping this thread once you're ready.

ping @jlisee

[jin]

I have a patch that does essentially the same thing. Can we merge this now, and fix the nit later?

[laurentlb]

@phst Shall we merge this?

[phst]

@phst Shall we merge this?

Yes, that's fine with me. We can fix the nits afterwards.

[laurentlb]

I can't merge now, there are conflicts.

@jlisee, could you update your branch?

[sellout]

It would be good to also have the prompts here use the the variable instead of hard-coding "bazel".

[sellout]

Since this is the kind of thing that is often project local (i.e., in .dir-locals.el), it'd be useful to add a :safe field.

From the Emacs info page:

   When defining a user option using ‘defcustom’, you can set its
‘safe-local-variable’ property by adding the arguments ‘:safe FUNCTION’
to ‘defcustom’ (*note Variable Definitions::).  However, a safety
predicate defined using ‘:safe’ will only be known once the package that
contains the ‘defcustom’ is loaded, which is often too late.  As an
alternative, you can use the autoload cookie (*note Autoload::) to
assign the option its safety predicate, like this:

     ;;;###autoload (put 'VAR 'safe-local-variable 'PRED)

The safe value definitions specified with ‘autoload’ are copied into the
package’s autoloads file (‘loaddefs.el’ for most packages bundled with
Emacs), and are known to Emacs since the beginning of a session.