Issues between openmp and llvm

[Shane Ambler]

I am testing an update to graphics/blender and seeing if I can use
devel/openmp as a dependency to prevent forcing the choice of compiler.

This works fine when openmp is pre-installed but fails if llvm[40|devel]
is installed before checking if libomp exists.

As the copy of libomp.so installed by llvm is found, devel/openmp does
not get installed.

 > ... libomp.so - found (/usr/local/llvm-devel/lib/libomp.so)

The issue is that the build then fails because cc/ld is looking for
openmp files in /usr/local where they should be installed.

This can fail on the host system as well as in poudriere. In poudriere
it only fails if blenders CYCLESOSL option is enabled which now installs
llvm40 before checking for libomp.so.

-- 
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Shane Ambler