c++ - Linking not working in homebrew's cmake since Mojave

Question

I've reproduced this symptom on two computers now, cmake seems to no longer look in /usr/local/lib (or more properly, $(brew --prefix)/lib) for Homebrew-provided libraries since upgrading my machine to macOS Mojave.

Although there are ways to circumvent this (e.g. search for homebrew prefix using EXECUTE_PROCESS; add the result to LINK_LIBRARIES(...) command) none are ideal. What changed in Mojave to break this behavior?

The temporary workaround is to add the following to CMakeLists.txt:

# WARNING: Don't hard-code this path
LINK_DIRECTORIES(/usr/local/lib)

I've already tried brew doctor and updated all homebrew packages to no avail.

The specific error that cmake (make) shows is:

ld: library not found for -l<somelib>

I've asked the question on the Homebrew forums and the Apple developer forums.

Answer 1

Ran into a related (?) issue while trying to pip install psycopg2 in a Django app under OS X Mojave (10.14). I was getting the following errors:

ld: library not found for -lssl
clang: error: linker command failed with exit code 1 (use -v to see invocation)
error: command 'clang' failed with exit status 1

The short explanation: ? As of High Sierra, /usr/local is no longer chown-able... ?

The solution: change permissions for /usr/local to allow Homebrew to create links.

I adapted the solution to my needs. Then I was finally able to run pip install psycopg2. Here is the sequence of commands (update: inside your project root i.e. where you see manage.py).

First

sudo chown -R $(whoami) $(brew --prefix)/*

Then

brew reinstall openssl
export LDFLAGS="-L/usr/local/opt/openssl/lib"
export CPPFLAGS="-I/usr/local/opt/openssl/include"
pip install psycopg2