[gitoxide] Use LLVMCompilerRT_jll to provide libclang_rt.osx.a (#4648)

Author: giordano

G/gitoxide/build_tarballs.jl

@@ -1,6 +1,6 @@
 # Note that this script can accept some limited command-line arguments, run
 # `julia build_tarballs.jl --help` to see a usage message.
-using BinaryBuilder
+using BinaryBuilder, Pkg
 
 name = "gitoxide"
 # Note: upstream doesn't seem to tag new versions of `gitoxide` recently, but
@@ -16,6 +16,10 @@ sources = [
 # Bash recipe for building across all platforms
 script = raw"""
 cd $WORKSPACE/srcdir/gitoxide*/
+if [[ "${target}" == *-apple-* ]]; then
+    # Help the linker find `libclang_rt.osx.a`
+    export RUSTFLAGS="-Clink-args=-L${libdir}/darwin"
+fi
 cargo build --release
 install -Dvm 755 "target/${rust_target}/release/ein${exeext}" "${bindir}/ein${exeext}"
 install -Dvm 755 "target/${rust_target}/release/gix${exeext}" "${bindir}/gix${exeext}"
@@ -25,8 +29,6 @@ install_license LICENSE-*
 # These are the platforms we will build for by default, unless further
 # platforms are passed in on the command line
 platforms = supported_platforms()
-# macOS builds require libclang_rt.osx.a static library, which isn't in the SDK
-filter!(!Sys.isapple, platforms)
 # PowerPC and 32-bit ARM not supported by sha1-asm
 filter!(p -> arch(p) ∉ ("powerpc64le", "armv6l", "armv7l"), platforms)
 # Rust toolchain for i686 Windows is unusable
@@ -39,7 +41,9 @@ products = [
 ]
 
 # Dependencies that must be installed before this package can be built
-dependencies = Dependency[
+dependencies = [
+    # We need libclang_rt.osx.a for linking the program.
+    BuildDependency(PackageSpec(name="LLVMCompilerRT_jll", uuid="4e17d02c-6bf5-513e-be62-445f41c75a11", version=v"12.0.0"); platforms=filter(Sys.isapple, platforms)),
 ]
 
 # Build the tarballs, and possibly a `build.jl` as well.