Re: how to let configure know include and library path for library foo?

[Bob Friesenhahn]

On Thu, 24 Jan 2019, Sébastien Hinderer wrote:
> I assume it's good to also provide three options for each library: one
> to let configure know whether it should be enabled or not, i.e. an
> equivalent of --with-x, and two options to specify the header and
> library directories. But, of course, it is not possible to define
> --foo-includes=DIR and --foo-libraries=DIR as is done for X, so is one
> supposed to use AC_ARG_VAR to achieve this?

Many configure scripts do such things but if such options are enabled 
by default then it harms the user by removing the freedom to specify 
the search order for headers and libraries, and possibly ordering in 
CFLAGS/CPPFLAGS.  The reason why the freedom has been lost is that the 
ordering is then determined by code in the configure script.

It is not uncommon for a user who compiles a package from source code 
to have additional packages similarly pre-compiled/installed in 
different directories than used by the operating system and for the 
user to want to assure that preferred versions are used.

Bob
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Bob Friesenhahn
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