<chapter xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xml:id="chap-platform-nodes"> <title>Platform Notes</title> <section xml:id="sec-darwin"> <title>Darwin (macOS)</title> <para>Some common issues when packaging software for darwin:</para> <itemizedlist> <listitem> <para> The darwin <literal>stdenv</literal> uses clang instead of gcc. When referring to the compiler <varname>$CC</varname> or <command>cc</command> will work in both cases. Some builds hardcode gcc/g++ in their build scripts, that can usually be fixed with using something like <literal>makeFlags = [ "CC=cc" ];</literal> or by patching the build scripts. </para> <programlisting> stdenv.mkDerivation { name = "libfoo-1.2.3"; # ... buildPhase = '' $CC -o hello hello.c ''; } </programlisting> </listitem> <listitem> <para> On darwin libraries are linked using absolute paths, libraries are resolved by their <literal>install_name</literal> at link time. Sometimes packages won't set this correctly causing the library lookups to fail at runtime. This can be fixed by adding extra linker flags or by running <command>install_name_tool -id</command> during the <function>fixupPhase</function>. </para> <programlisting> stdenv.mkDerivation { name = "libfoo-1.2.3"; # ... makeFlags = stdenv.lib.optional stdenv.isDarwin "LDFLAGS=-Wl,-install_name,$(out)/lib/libfoo.dylib"; } </programlisting> </listitem> <listitem> <para> Some packages assume xcode is available and use <command>xcrun</command> to resolve build tools like <command>clang</command>, etc. This causes errors like <code>xcode-select: error: no developer tools were found at '/Applications/Xcode.app'</code> while the build doesn't actually depend on xcode. </para> <programlisting> stdenv.mkDerivation { name = "libfoo-1.2.3"; # ... prePatch = '' substituteInPlace Makefile \ --replace '/usr/bin/xcrun clang' clang ''; } </programlisting> <para> The package <literal>xcbuild</literal> can be used to build projects that really depend on Xcode, however projects that build some kind of graphical interface won't work without using Xcode in an impure way. </para> </listitem> </itemizedlist> </section> </chapter>