Isn't it possible to replace MASTER_SITES by USE_GITHUB?

This could be replaced by USES+=blaslapack

Not at this moment, julia's build system will try to download its libs during the bulid stage.
By Downloading the full tar instead this is avoided.

julia depends on openblas not blas,
did you mean USES+=blaslapack:openblas

On second thought if i can patch julia's build system so that it wont call out during the build stage and use GH_TUPLE from ports to Download its libs in advance i can use USE_GITHUB, let me look in to this a bit further.

If the /releases/ tarball is manually built to contain more vendored stuff than just the auto archive of a git tag, it is actually better to use this URL. e.g. I use this in net-im/fractal (though with gitlab). Do not switch to USE_GITHUB in that case!

^ wait what?

^ no need to specify the same port multiple times.

^ could be done more declaratively without an if, via NATIVE_MAKE_ARGS

^you could think of adding 1.7 via a PLIST_SUB -- depending on how often this version is bumped, this could greatly reduce the churn on the plist.

^this should now no longer be required for the NATIVE option. You can move the variables up to the normal options block.

^ this seems also to get removed in the DOCS-on target --- why not consolidate it?

"LIB_DEPENDS" has to appear earlier.

use a tab (not space) after a variable name

contiguous blank lines (> 1 lines) found.

Mostly a nitpick, but how about

Can you put an explanation for ONLY_FOR_ARCHS in the comment? Why is it only available for amd64?

Another style nitpick: add another tab symbol to align 7z... line with BUILD_DEPENDS below.

I'm a bit confused by this check. We do have USES=blaslapack:openblas unconditionally, so it should always be available. Why perform compile-check?

The test is to see if openblas was built with the INTERFACE64 knob on or off and set julia to build accordingly.

Hard-coding this will break configure phase in case of different GCC_DEFAULT.

what about GCC_VERSION?

This could be put in a regular post-install target: $STRIP_CMD is only set to /usr/bin/strip when $WITH_DEVUG is not defined, else it is set to true.

Can' this be done without nested loop?

.for file in .codecov.yml .travis.yml appveyor.yml bors.toml .gitignore source-extracted .github
${FIND} ${STAGEDIR}${PREFIX}/${INSTALLDIR}/share/julia/stdlib/v${PORTVERSION:R} -name ${file}
.endfor

How about doing the following changes about this variable:

1. Rename it to JULIA to bring it in sync with pkg-plist substitution.
2. Remove PKGNAMESUFFIX from its value, as it is empty anyways. Or did you intended to use DISTVERSIONSUFFIX?
3. Remove the julia/ part from the beginning. Right now the path to Julia stuff contains /julia/julia/ twice.

This is probably a no-op, since you don't define USE_GPL_LIBS anywhere. This should probably be changed to just USE_GPL_LIBS=0.

Do we need DEBUG_VARS_OFF= FORCE_ASSERTIONS=0 for this to work properly?

Why do we need the -stdlib=libc++ flag? This is default for our Clang anyways, however some users are using GCC to compile stuff. Wouldn't this flag cause problems in such case?