In MPFR, don't delete old libraries

[jdemeyer]

libmpfr (and libmpfr and libmpc, #12515) are run-time dependencies of gcc (#12369). These therefore become build-time dependencies of Sage. When these libraries are deleted during installation of mpfr, gcc stops working, causing build failures in parallel builds.

Since there is no clear reason why the old libraries should be deleted, we simply don't delete them. The mpir spkg-install already doesn't delete libraries and mpc will be fixed in #12515.

spkg: http://boxen.math.washington.edu/home/jdemeyer/spkg/mpfr-2.4.2.p2.spkg

CC: @jpflori

Component: packages: standard

Author: Jeroen Demeyer

Reviewer: John Palmieri

Merged: sage-5.0.beta6

Issue created by migration from https://trac.sagemath.org/ticket/12548

[jdemeyer]

Author: Jeroen Demeyer

[jdemeyer]

Diff for the mpfr spkg, for review only

[jdemeyer]

comment:2

Attachment: mpfr-2.4.2.p2.diff.gz

[jhpalmieri]

comment:4

Looks good to me. Why even delete the headers?

[jhpalmieri]

Reviewer: John Palmieri

[jpflori]

comment:5

Isn't the point of deleting the old librairies to not have tons of old librairies inside lib/ if Sage keeps on getting updated?

You might argue that it's not a big deal, because Sage is already so big, but...

And wasn't #12366 sufficient for building gcc?

[jdemeyer]

comment:7

Replying to @jpflori:

Isn't the point of deleting the old librairies to not have tons of old librairies inside lib/ if Sage keeps on getting updated?

Probably. But this wouldn't work here, as deleting the old mpir/mpfr/mpc libraries would mean that gcc stops working. There are work-arounds, but they would make the build/upgrade process a lot more complicated.

And wasn't #12366 sufficient for building gcc?

For serial builds, #12366 is sufficient. The problem with parallel builds is that there is a cerain time between the deleting of the old mpfr libraries and the installation of the new mpfr libraries. During that time, a gcc in a parallel build wouldn't work anymore.

[jdemeyer]

Merged: sage-5.0.beta6