Bug 280642 – sci-libs/mathgl-1.8.1 request gcc to have been build with openmp

• Status: RESOLVED WONTFIX
• Product: Gentoo Linux

[Description François Bissey 2009-08-07 11:12:55 UTC]

The mathgl makefile hardcode the use of -openmp -lgomp in its makefile
causing the compilation to fails on systems where gcc has been built without
this features (because I have an antique system with only one CPU).
I already reported the problem to the maintainer previously and a patch
is ready to remove the compulsory behavior but was never applied to the tree.
I just stumbled on the issue again.

Reproducible: Always

Steps to Reproduce:
1. USE="-openmp" emerge -v gcc
2. emerge -v mathgl
3. Failure

[Comment 1 François Bissey 2009-08-07 11:14:57 UTC]

Created attachment 200486 [details, diff]
Andrey Grozin patch to correct the behavior

This is a patch sent to me by the maintainer of mathgl to correct the problem
a few month back.

[Comment 2 François Bissey 2009-08-12 12:19:05 UTC]

Created attachment 201021 [details, diff]
better patch to enable autoconfiguration of openmp rather than just disabling it.

Patch configure.ac and mgl/Makefile.am - openmp can now be enabled
with --enable-openmp. 
It has to be tested on an openmp enabled machine.
Patched ebuild to follow shortly.

[Comment 3 François Bissey 2009-08-12 12:20:02 UTC]

Created attachment 201022 [details, diff]
patch to mathgl-1.8.1.ebuild to include openmp useflag.

[Comment 4 Sébastien Fabbro (RETIRED) 2009-08-26 06:55:26 UTC]

The patch should not be gcc specific. The user might want to build with another openmp able compiler. See fftw package for an example (or many other openmp packages).

[Comment 5 François Bissey 2009-09-22 12:19:20 UTC]

OK, after failing miserably at patching 1.8.1 properly as suggested
by bicatali, I managed to do something for version 1.9.
The upgrade to libtool 2.2 helped as it showed why the previous attempt had
failed. So a bit of summary:
I looked at fftw as suggested and used the m4 macro shipped with it as patched 
in the fftw ebuild. I put it in config rather than a m4 folder as it would
conflict with an option in Makefile.am (thanks libtool 2.2).
I followed flameeyes autotool mythbusters guideline to add an openmp configure
option "on" by default so that it would cause minimum disruption for upstream.
I included a detailed compiler check in the ebuild as well.
Patch to follow. 

[Comment 6 François Bissey 2009-09-22 12:20:57 UTC]

Created attachment 204914 [details, diff]
patch to add the openmp useflag to the ebuild

[Comment 7 François Bissey 2009-09-22 12:21:32 UTC]

Created attachment 204915 [details]
openmp m4 macro

[Comment 8 François Bissey 2009-09-22 12:22:20 UTC]

Created attachment 204917 [details, diff]
patch configure.ac and mgl/Makefile.am to add openmp configurability

[Comment 9 François Bissey 2009-09-22 12:23:23 UTC]

Aaaaa further note I have no openmp enabled machine at the moment, so
it needs testing with one.

[Comment 10 Justin Lecher (RETIRED) 2010-06-30 22:18:50 UTC]

No omp support anymore