Fix linking issue on macOS

[kenohassler]

After using make install, ecdsautil would crash on my Mac with the following error message:

dyld[98560]: Library not loaded: @rpath/libecdsautil.0.dylib
Referenced from: <0202E251-97CE-3FCF-A529-5B723AC042A0> /usr/local/bin/ecdsautil
Reason: no LC_RPATH's found

Basically, dyld does not know where to load the library from. To fix this, define LC_RPATH by setting INSTALL_RPATH via cmake. This seems to be an Apple thing, but I used CMAKE_INSTALL_PREFIX to be platform-agnostic just to be sure.

Additionally, I addressed an unrelated cmake warning by changing the capitalization of "libuecc". I tested building on macOS 26 and Debian 13, both worked flawlessly.

[neocturne]

Hmm, setting the rpath should only be necessary when the dylib is installed to a non-standard library location - /usr/local/lib should work by default though according to https://developer.apple.com/library/archive/documentation/DeveloperTools/Conceptual/DynamicLibraries/100-Articles/UsingDynamicLibraries.html. Maybe some cache needs to be updated?

I would it consider bad style to set an rpath when it is not actually necessary - most software does not set one.

[kenohassler]

Hi, thanks for taking a closer look. As it definitely didn't work on my system, I tried to find more up-to-date documentation.
man dyld gives me the following:

DYLD_FALLBACK_LIBRARY_PATH
This is a colon separated list of directories that contain libraries. If a dylib is not found at its install path, dyld uses this as a list of directories to search for the dylib.

For new binaries (Fall 2023 or later) there is no default. For older binaries, there is a default fallback search path of: /usr/local/lib:/usr/lib.

I would guess this means the default interpretation of @rpath changed as well?

[neocturne]

See also https://cmake.org/cmake/help/latest/prop_tgt/MACOSX_RPATH.html and https://cmake.org/cmake/help/latest/policy/CMP0042.html, but my knowledge of macos is not sufficient to interpret what "using rpath" means here.

[kenohassler]

Nope, this didn't help either. I have tried setting MACOSX_RPATH FALSE in the target properties in src/lib/CMakeLists.txt. After make install, the following error is thrown:

dyld[10011]: Library not loaded: libecdsautil.0.dylib
  Referenced from: <0499A25C-9F48-355D-B026-7D1474508474> /usr/local/bin/ecdsautil
  Reason: tried: 'libecdsautil.0.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OSlibecdsautil.0.dylib' (no such file), 'libecdsautil.0.dylib' (no such file), '/Users/<private>/ecdsautils/build/libecdsautil.0.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/Users/<private>/ecdsautils/build/libecdsautil.0.dylib' (no such file), '/Users/<private>/ecdsautils/build/libecdsautil.0.dylib' (no such file)

The manual page on MACOSX_RPATH also states that

Runtime paths will also be embedded in binaries using this target and can be controlled by the INSTALL_RPATH target property on the target linking to this target.

So I think setting INSTALL_RPATH might actually be the way to go. Happy to test something else though.