disable readline support by default on most unices ?

[Jim <djvaios@...>]

On 5/10/19, Scott Morgan <blumf@blueyonder.co.uk> wrote:
> readline is just for the (optional) stand-alone executable, not the
> language itself, which needs to be as portable as possible
> (i.e. ANSI C only)

i already understood that very well.

but linking against libreadline should be disabled by default
on platforms where it is unsure if the lib/headers are installed
(in the default install, true for Linux, the commercial SysV
(though Solaris could be an exception here) unices and of
course the BSDs which are (rightfully !) not keen to introduce
unnecessary extra dependencies on GNUware. i dunno what gets
included in the macOS default install.).

building with readline support can be easily left to package/port maintainers.

and btw:
libnl etc exist in the default Solaris install, so there is no problem with
linking against them. probably the same for libpthread on Linux.