Script package for checking presence of system libxml2 (polymake and igraph prerequisite)

[mkoeppe]

Apparently some Linux systems don't come with libxml2 installed, which is a polymake prerequisite.

mkoeppe.sphere$ make polymake
...
[polymake-3.4] checking libxml2 installation ... Could not find configuration program xml2-config for library libxml2.
[polymake-3.4] Probably you need to install development package for it;
[polymake-3.4] usually it is called libxml2-devel or similarly.
[polymake-3.4] If the library is installed at a non-standard location,
[polymake-3.4] please specify it in option --with-libxml2

We add spkg-configure and system package information

CC: @dimpase @dcoudert

Component: packages: optional

Author: Matthias Koeppe

Branch/Commit: 256ddfc

Reviewer: Dima Pasechnik, David Coudert

Issue created by migration from https://trac.sagemath.org/ticket/27921

[mkoeppe]

Description changed:

--- 
+++ 
@@ -9,3 +9,11 @@
 [polymake-3.4] If the library is installed at a non-standard location,
 [polymake-3.4] please specify it in option --with-libxml2
 ```
+
+Upstream:
+
+```
+wget -P upstream ftp://xmlsoft.org/libxml2/libxml2-2.9.9.tar.gz
+```
+
+

[dimpase]

comment:2

I would rather add this to general Sage pre-reqs. And a test for it in the main configure.ac. Let us try to stop vendoring everything that comes across...

[mkoeppe]

comment:3

I appreciate your efforts with spkg-configure.m4; but I don't support adding more prerequisites to Sage. Sage-the-distribution works well for installing lots of math software on poorly maintained university computers. My goal in this ticket is to bring the polymake package to the same standard - make it as easy to install as other sage packages.

[mkoeppe]

Branch: u/mkoeppe/package_libxml2__polymake_prerequisite_

[mkoeppe]

comment:5

Replying to @mkoeppe:

I don't support adding more prerequisites to Sage.

To clarify, I don't support depending on more packages to exist in the system for a Sage installation to succeed.

---

New commits:

dfc25f3

Add package libxml2, make it a polymake dependency

[mkoeppe]

Commit: dfc25f3

[mkoeppe]

Author: Matthias Koeppe

[sagetrac-git]

Changed commit from dfc25f3 to 3d4e807

[sagetrac-git]

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

3d4e807

fix typo

[dimpase]

comment:9

a library should only be vendored if on a system supported by Sage it is either not available, or broken. Otherwise it is a bloat that is killing the project, rather than improving it.

there are already other optional packages, e.g. igraph, in Sage that require libxml2.

[sagetrac-git]

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

e5f95ad

Add libxml2 as dependency of igraph

[sagetrac-git]

Changed commit from 3d4e807 to e5f95ad

[dimpase]

comment:12

there is also R package xml2, which uses libxml2, and which some people install --- and which this ticket potentially breaks.

this is yet another reason why I don't like vendoring standard libraries - because you end up spending all your time chasing up stuff like this, and it ends up like iconv package, which is still there, but we don't install it on anything but (maybe) cygwin, or (broken platform) solaris.

[mkoeppe]

comment:13

Lots of good points. Turns out on the system where I was trying to compile polymake, also perl-devel and Term::ReadKey are missing.
So I'm setting this ticket to 'wishlist' status for now.

[mkoeppe]

Description changed:

--- 
+++ 
@@ -10,10 +10,4 @@
 [polymake-3.4] please specify it in option --with-libxml2
 ```
 
-Upstream:
-
-```
-wget -P upstream ftp://xmlsoft.org/libxml2/libxml2-2.9.9.tar.gz
-```
-
-
+We add `spkg-configure` and system package information