statik(true) doesn't do anything on macOS

[kornelski]

In macOS passing --static to pkg-config is not enough to get the library linked statically. For almost all packages both .a and .dylib exist, and names specified by pkg-config are ambiguous.

$ pkg-config --static --libs lcms2
-L/usr/local/Cellar/little-cms2/2.8/lib -llcms2 -lm
$ pkg-config --libs lcms2
-L/usr/local/Cellar/little-cms2/2.8/lib -llcms2

Instructions printed by pkg-config don't specify that static linking was requested:

cargo:rustc-link-search=native=/usr/local/Cellar/little-cms2/2.8/lib
cargo:rustc-link-lib=lcms2
cargo:rustc-link-lib=m

So rustc invocation switches to dynamic linking:

Running rustc … -l z -l lcms2 -l m…

otool -L target/release/test
    /usr/local/opt/little-cms2/lib/liblcms2.2.dylib (compatibility version 3.0.0, current version 3.8.0)

I think this library should be printing rustc-link-lib=static=lcms2 when .statik(true) was specified (but only for the probed library, e.g. don't statically link libz if libpng was probed)

[alexcrichton]

This is likely because the contents of /usr are considered to be part of the system and always preferred to link dynamically rather than statically. #37 may be related?

[kornelski]

Yes, is_system is definitely wrong for macOS. System libraries are in /System/Library/ and /usr/lib.

But /usr/local/{lib,opt} is used by 3rd party homebrew.

[alexcrichton]

Seems reasonable to patch! Want to send a PR?