[CMake] Setting RPATH lookup on macOS

[Kyle Edwards]

On Wed, 2019-09-11 at 17:33 -0400, Michael Jackson wrote:
> Already looked on google and at the CMake documentation but
> everything listed does not seem to work so here is the setup.
> 
> I am using MKL and I have a home grown FindMKL since there isn’t an
> official one. Inside that is the typical find_library() calls which
> will find the libraries just fine. One of those libraries is a
> dynamic library (.dylib). Using otool -L on that library the
> install_name is encoded as @rpath. 
> 
> Now I have my add_executable(foo…) and target_link_libraries (Foo
> ${MKL_LIBRARIES} ).
> 
> Everything compiles and links fine. The issue is at runtime. The app
> will not launch because libmkl_rt.dylib is not loaded because the
> path to that library is not encoded into the executable.
> 
> 639:[mjackson at ferb:ifort-release]$ otool -l
> Bin/EMsoftWorkbench.app/Contents/MacOS/EMsoftWorkbench | grep "path"
>          name @rpath/libEbsdLib.dylib (offset 24)
>          name @rpath/libmkl_rt.dylib (offset 24)
>          name @rpath/QtOpenGL.framework/Versions/5/QtOpenGL (offset
> 24)
>          name @rpath/QtNetwork.framework/Versions/5/QtNetwork (offset
> 24)
>          name @rpath/QtConcurrent.framework/Versions/5/QtConcurrent
> (offset 24)
>          name @rpath/QtWidgets.framework/Versions/5/QtWidgets (offset
> 24)
>          name @rpath/QtGui.framework/Versions/5/QtGui (offset 24)
>          name @rpath/QtCore.framework/Versions/5/QtCore (offset 24)
>          path /Users/Shared/EMsoft_SDK-ifort/EbsdLib-0.1-Release/lib
> (offset 12)
>          path /Users/Shared/EMsoft_SDK-
> ifort/Qt5.12.3/5.12.3/clang_64/lib (offset 12)
> 
> 
> Oddly the Qt libraries and one of my own libraries do get their
> rpaths encoded. I feel like I need to append to the RPATH that gets
> encoded into the executable but I am not really figuring out how to
> do that.
> 
> Help....

Have you looked at the BUILD_RPATH and INSTALL_RPATH properties?

https://cmake.org/cmake/help/latest/prop_tgt/BUILD_RPATH.html
https://cmake.org/cmake/help/latest/prop_tgt/INSTALL_RPATH.html

Kyle