replace the use of build_targets in Clang and LLVM builds

[branfosj]

(created using eb --new-pr)

#2449 added the functionality to build for multiple targets. This means that the items in build_targets are looped over and run as separate builds. However, the LLVM and Clang easyblocks use build_targets to set the machine types to build for in the CMake configure step. Without it we see make X86 -j 12 when building and that leads to the error make: *** No rule to make target 'X86'. Stop.

[SebastianAchilles]

Test report by @SebastianAchilles

Overview of tested easyconfigs (in order)

• SUCCESS LLVM-11.1.0-GCCcore-10.3.0.eb

Build succeeded for 1 out of 1 (1 easyconfigs in total)
rocky8-eb - Linux rocky linux 8.4, x86_64, Intel(R) Core(TM) i7-6900K CPU @ 3.20GHz (broadwell), Python 3.6.8
See https://gist.github.com/9b081197932c2d847a8c5f6bf921c52f for a full test report.

[SebastianAchilles]

Test report by @SebastianAchilles

Overview of tested easyconfigs (in order)

• SUCCESS LLVM-11.1.0-GCCcore-10.3.0.eb

Build succeeded for 1 out of 1 (1 easyconfigs in total)
centos8-eb - Linux centos linux 8.3.2011, x86_64, Intel(R) Core(TM) i7-8700 CPU @ 3.20GHz (skylake), Python 3.6.8
See https://gist.github.com/ee07c99a4b7ba8b6a7c29234293e3c50 for a full test report.

[branfosj]

Test report by @branfosj

Overview of tested easyconfigs (in order)

• SUCCESS LLVM-11.1.0-GCCcore-10.3.0.eb
• SUCCESS Clang-11.0.1-GCCcore-10.2.0.eb
• SUCCESS LLVM-8.0.1-GCCcore-8.3.0.eb
• SUCCESS CMake-3.12.1-GCCcore-7.3.0.eb
• SUCCESS Clang-7.0.1-GCC-7.3.0-2.30.eb

Build succeeded for 5 out of 5 (4 easyconfigs in total)
bear-pg0206u03b.bear.cluster - Linux RHEL 8.3, x86_64, Intel(R) Xeon(R) Gold 6248 CPU @ 2.50GHz (cascadelake), Python 3.6.8
See https://gist.github.com/7a352d10a08ca060cc7b8718fc031112 for a full test report.

[SebastianAchilles]

Test report by @SebastianAchilles

Overview of tested easyconfigs (in order)

• SUCCESS LLVM-11.1.0-GCCcore-10.3.0.eb

Build succeeded for 1 out of 1 (1 easyconfigs in total)
jrlogin11.jureca - Linux centos linux 8.3.2011, x86_64, AMD EPYC 7742 64-Core Processor, Python 3.6.8
See https://gist.github.com/c7253f9fc536f09c551726dac003dcff for a full test report.

[boegel]

@branfosj Hmm, doesn't this show that the changes made in #2449 are not backwards compatible?

Or do we consider this an unlucky clash between ConfigureMake and the custom Clang easyblock?

Is there any way we can avoid this in ConfigureMake?

[branfosj]

#2449 looks to be a good change, but it does cause this bug. The only alternative I can see is to rename the build_targets that #2449 introduced to something else, such as build_step_targets or build_cmd_targets.

[branfosj]

I've put the alternative fix in #2479 - renaming built_targets in ConfigureMake.

[branfosj]

closing in favour of #2479

[boegel]

#2479 is a better fix imho, I think it's a lot less likely that build_cmd_targets is used as a custom easyconfig parameter in existing easyblocks (outside of our easyblocks repo)