Platform Notes
Darwin (macOS)
Some common issues when packaging software for Darwin:
The Darwin stdenv uses clang instead of gcc. When
referring to the compiler $CC or cc
will work in both cases. Some builds hardcode gcc/g++ in their build
scripts, that can usually be fixed with using something like
makeFlags = [ "CC=cc" ]; or by patching the build
scripts.
stdenv.mkDerivation {
name = "libfoo-1.2.3";
# ...
buildPhase = ''
$CC -o hello hello.c
'';
}
On Darwin, libraries are linked using absolute paths, libraries are
resolved by their install_name at link time. Sometimes
packages won't set this correctly causing the library lookups to fail at
runtime. This can be fixed by adding extra linker flags or by running
install_name_tool -id during the
fixupPhase.
stdenv.mkDerivation {
name = "libfoo-1.2.3";
# ...
makeFlags = stdenv.lib.optional stdenv.isDarwin "LDFLAGS=-Wl,-install_name,$(out)/lib/libfoo.dylib";
}
Even if the libraries are linked using absolute paths and resolved via
their install_name correctly, tests can sometimes fail
to run binaries. This happens because the checkPhase
runs before the libraries are installed.
This can usually be solved by running the tests after the
installPhase or alternatively by using
DYLD_LIBRARY_PATH. More information about this variable
can be found in the
dyld
1 manpage.
dyld: Library not loaded: /nix/store/7hnmbscpayxzxrixrgxvvlifzlxdsdir-jq-1.5-lib/lib/libjq.1.dylib
Referenced from: /private/tmp/nix-build-jq-1.5.drv-0/jq-1.5/tests/../jq
Reason: image not found
./tests/jqtest: line 5: 75779 Abort trap: 6
stdenv.mkDerivation {
name = "libfoo-1.2.3";
# ...
doInstallCheck = true;
installCheckTarget = "check";
}
Some packages assume xcode is available and use xcrun
to resolve build tools like clang, etc. This causes
errors like xcode-select: error: no developer tools were found at
'/Applications/Xcode.app'
while the build doesn't actually depend
on xcode.
stdenv.mkDerivation {
name = "libfoo-1.2.3";
# ...
prePatch = ''
substituteInPlace Makefile \
--replace '/usr/bin/xcrun clang' clang
'';
}
The package xcbuild can be used to build projects that
really depend on Xcode. However, this replacement is not 100%
compatible with Xcode and can occasionally cause issues.