add support for toolchain options like 'extra_cxxflags' to specify extra compiler options

[mboisson]

Tested with a NAMD recipe.

[boegel]

@mboisson do we want to be able to specify separate/different flags for C and C++ compilers (i.e. in $CFLAGS and $CXXFLAGS)?

[boegel]

also, we're missing an enhanced test for this...

[mboisson]

@mboisso do we want to be able to specify separate/different flags for C and C++ compilers (i.e. in $CFLAGS and $CXXFLAGS)?

It would be nice, but there is no current distinction between CFLAGS and CXXFLAGS in the code for any other parameters. I am not sure why this is the case, but the purpose of this PR is not to introduce such as split (even though I think there should be one).

[mboisson]

also, we're missing an enhanced test for this...

I have to say I'm lost when it comes to tests. Any pointers as to what I should do ? Extra arguments can be anything. There is no sample code that I can compile for anything.

[mboisson]

Any guidance as to how to create the missing tests ?

[boegel]

@mboisson Examples of tests that check what goes into $CFLAGS & co and fiddle with toolchain options are in test/framework/toolchain.py, see for example test_misc_flags_shared

We should really extend this to cover $CXXFLAGS separately though, I can help with that, hopefully sometime next week.

Are you OK with not including this in EasyBuild v3.2.0 (which I hope to release next week)?

[mboisson]

Sure. We have merged it in our own fork anyway, so we are using it.

[mboisson]

Did you have time to extend on this ?

[boegel]

@mboisson I'm afraid not, not sure when I'll find the time to flesh this out...

[akesandgren]

@mboisson What is the status of this? Looks like we need to kick travis if we want to move forward on it...

[mboisson]

Mmm, the status is issue-necropsy :P I haven't touched this for two years. @boegel wanted some changes

[bartoldeman]

I discussed this with @boegel briefly last week, had forgotten you filed a PR... basically this is one of only two changes we have left in our fork (the other change pertains to the permissions of the temporary file folders /tmp/eb-* so we can look at each others' logs on the build node, but that is still to be PR'ed.

He mentioned that a generic --optflags CLI option is another way to do this and we could have a good look at that.

Neither of us is working this week though :)

[boegel]

Tested with Boost easyconfig from easybuilders/easybuild-easyconfigs#11642 that uses extra_cxxflags in toolchainopts, works like a charm!

Thanks a lot both @mboisson and @bartoldeman!