polymake: Add system package lists for Perl prereqs

[mkoeppe]

We add the lists of system packages providing polymake's Perl prerequisites so that ./configure will include them in the list of suggested packages.

At least for the distributions that provide these packages, this is more reliable than depending on users reading build/pkgs/polymake/SPKG.txt.

This is achieved by adding them in distros/ of a new script package perl_cpan_polymake_prereq (a new dependency of polymake) with an spkg-configure.m4 that checks for the prerequisites and an spkg-install that always fails.

(See also the more ambitious #27763, which will not be ready for 9.1.)

[jhpalmieri]

Is this ready for review? Some comments, in any case: when I use this on OS X, perl_cpan_polymake_prereq fails to build, and its log file says:

.../sage-9.1.beta7/build/bin/sage-logger: line 91: .../sage-9.1.beta7/build/pkgs/perl_cpan_polymake_prereq/spkg-install: Permission denied

A key point is that it doesn't have a line matching the regular expression ^Error, so I see this:

The following package(s) may have failed to build (not necessarily
during this run of 'make polymake'):

It is safe to delete any log files and build directories, but they
contain information that is helpful for debugging build problems.
WARNING: If you now run 'make' again, the build directory of the
same version of the package will, by default, be deleted. Set the
environment variable SAGE_KEEP_BUILT_SPKGS=yes to prevent this.

I assume you're going to make spkg-install fail with a meaningful error message?

---

New commits:

​fa4ec71	bootstrap: Put SAGE_SPKG_ENABLE(...) before SAGE_SPKG_CONFIGURE_...
​12c2b2a	Add script package perl_cpan_polymake_prereq

[mkoeppe]

Thanks for the feedback. This ticket is not ready for review.

What it is missing (the same applies to the "libnauty" business on #27952) is a way for optional packages to signal configure-time errors ONLY if they are configured to be installed.

This is trickier than it sounds because optional packages may be dependencies of other optional packages. (See also #29363 At the end of configure, indicate which optional/experimental packages are configured to be installed)

[mkoeppe]

See also - #29498 Do not check for system packages of disabled optional packages

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

​b1936c3	bootstrap: Put SAGE_SPKG_ENABLE(...) before SAGE_SPKG_CONFIGURE_...
​109b86d	Add script package perl_cpan_polymake_prereq
​e6b8e80	build/pkgs/perl_cpan_polymake_prereq: Rename spkg-install to spkg-install.in

[dimpase]

+# known correct on Fedora 23 is a blast from the past. The names are still the same on Fedora 30.

[git]

Branch pushed to git repo; I updated commit sha1. This was a forced push. New commits:

​c02e263	build/pkgs/perl_cpan_polymake_prereq/type: Change to optional
​0958eb7	build/pkgs/perl_cpan_polymake_prereq/spkg-configure.m4: Only warn when polymake is going to be installed
​c19360e	build/pkgs/perl_cpan_polymake_prereq/distros/fedora.txt: Remove outdated comment
​41839e9	Add #! to build/pkgs/perl_cpan_polymake_prereq/spkg-install (script package!)

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​d4d832d

build/pkgs/perl_cpan_polymake_prereq/spkg-install: Better error message

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​18f1352

fixup

[git]

Branch pushed to git repo; I updated commit sha1. New commits:

​afb8a90	build/pkgs/perl_cpan_polymake_prereq/spkg-configure.m4: Remove code for issueing warnings - does not work because of m4 macro reordering
​9de4708	build/pkgs/polymake/SPKG.txt: Update

[dimpase]

without the description on #27763 it's a bit unclear what this is meant to do.

[dimpase]

lgtm

[mkoeppe]

Thanks!