Re: "make dist" and conditional build of autotool-enabled subpackage.

Dear Zack,

Thank you prompt reply, your answer looks quite reasonable.
I would execute AC_CONFIG_SUBDIRS() unconditionally, if
there's no way to escape :-)

I never had an idea making Y/configure skip the detailed
check by passing "--with-system-Y", sounds very smart.
I would try.

Thanks again!
mpsuzuki

On 2024/10/16 1:07, Zack Weinberg wrote:
> On Tue, Oct 15, 2024, at 10:38 AM, suzuki toshiya wrote:
>> I'm looking for a combination of the target to include sub-packages
>> which is built conditionally.
>>
>> A package "X" include a libary "Y" as a subpackage, like
> ...
>> Y is often installed as an external or system library, so X/configure
>> calls AC_CONFIG_SUBDIRS([Y]) in some cases, not always.
> 
> You need to call AC_CONFIG_SUBDIRS([Y]) unconditionally.  Many things
> break if you call it conditionally, not just what you have already
> tripped over.  Not only this, but Y's configure script needs to actually
> run and its Makefiles need to be generated unconditionally.  (The basic
> _issue_ is what you've already tripped over: Automake needs to know
> _statically_ all of the files included in package X.  But many other
> things besides "make dist" depend on this.)
> 
> Instead, I suggest that you have Y detect when it is being configured
> as an embedded subpackage that will not actually be used.  For example,
> if X decides to build Y based on the value of a --with-system-Y
> configure switch, Y's configure.ac can itself respond to --with-system-Y
> by skipping all its system probes and using Automake conditionals to
> avoid building the library.  As I recall, AC_CONFIG_SUBDIRS([Y]) will
> pass --with-system-Y down to Y's configure.ac, so you don't need to do
> anything special there.
> 
> zw
>