rust: fix musl build

srcpkgs/rust/files/musl.patch

@@ -1,11 +1,62 @@
---- rustc-1.28.0-src/src/librustc_target/spec/x86_64_unknown_linux_musl.rs.orig	2018-08-08 23:21:51.673454236 +0200
-+++ rustc-1.28.0-src/src/librustc_target/spec/x86_64_unknown_linux_musl.rs	2018-08-08 23:23:11.080834122 +0200
-@@ -11,7 +11,7 @@
- use spec::{LinkerFlavor, Target, TargetResult};
+From: Jakub Jirutka <jakub@jirutka.cz>
+Date: Sat, 08 Aug 2016 15:06:00 +0200
+Subject: [PATCH] Fix linux_musl_base for native musl host
+
+See https://github.com/rust-lang/rust/pull/40113
+
+--- a/src/librustc_target/spec/linux_musl_base.rs
++++ b/src/librustc_target/spec/linux_musl_base.rs
+@@ -13,53 +13,12 @@
+ pub fn opts() -> TargetOptions {
+     let mut base = super::linux_base::opts();
 
- pub fn target() -> TargetResult {
--    let mut base = super::linux_musl_base::opts();
-+    let mut base = super::linux_base::opts();
-     base.cpu = "x86-64".to_string();
-     base.max_atomic_width = Some(64);
-     base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-m64".to_string());
+-    // Make sure that the linker/gcc really don't pull in anything, including
+-    // default objects, libs, etc.
+-    base.pre_link_args_crt.insert(LinkerFlavor::Gcc, Vec::new());
+-    base.pre_link_args_crt.get_mut(&LinkerFlavor::Gcc).unwrap().push("-nostdlib".to_string());
+-
+     // At least when this was tested, the linker would not add the
+     // `GNU_EH_FRAME` program header to executables generated, which is required
+     // when unwinding to locate the unwinding information. I'm not sure why this
+     // argument is *not* necessary for normal builds, but it can't hurt!
+     base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-Wl,--eh-frame-hdr".to_string());
+
+-    // There's a whole bunch of circular dependencies when dealing with MUSL
+-    // unfortunately. To put this in perspective libc is statically linked to
+-    // liblibc and libunwind is statically linked to libstd:
+-    //
+-    // * libcore depends on `fmod` which is in libc (transitively in liblibc).
+-    //   liblibc, however, depends on libcore.
+-    // * compiler-rt has personality symbols that depend on libunwind, but
+-    //   libunwind is in libstd which depends on compiler-rt.
+-    //
+-    // Recall that linkers discard libraries and object files as much as
+-    // possible, and with all the static linking and archives flying around with
+-    // MUSL the linker is super aggressively stripping out objects. For example
+-    // the first case has fmod stripped from liblibc (it's in its own object
+-    // file) so it's not there when libcore needs it. In the second example all
+-    // the unused symbols from libunwind are stripped (each is in its own object
+-    // file in libstd) before we end up linking compiler-rt which depends on
+-    // those symbols.
+-    //
+-    // To deal with these circular dependencies we just force the compiler to
+-    // link everything as a group, not stripping anything out until everything
+-    // is processed. The linker will still perform a pass to strip out object
+-    // files but it won't do so until all objects/archives have been processed.
+-    base.pre_link_args.get_mut(&LinkerFlavor::Gcc).unwrap().push("-Wl,-(".to_string());
+-    base.post_link_args.insert(LinkerFlavor::Gcc, vec!["-Wl,-)".to_string()]);
+-
+-    // When generating a statically linked executable there's generally some
+-    // small setup needed which is listed in these files. These are provided by
+-    // a musl toolchain and are linked by default by the `musl-gcc` script. Note
+-    // that `gcc` also does this by default, it just uses some different files.
+-    //
+-    // Each target directory for musl has these object files included in it so
+-    // they'll be included from there.
+-    base.pre_link_objects_exe_crt.push("crt1.o".to_string());
+-    base.pre_link_objects_exe_crt.push("crti.o".to_string());
+-    base.post_link_objects_crt.push("crtn.o".to_string());
+-
+     // These targets statically link libc by default
+     base.crt_static_default = true;
+     // These targets allow the user to choose between static and dynamic linking.

srcpkgs/rust/template

@@ -155,7 +155,7 @@ do_configure() {
 	fi
 	case "$XBPS_TARGET_MACHINE" in
 	*-musl)
-		configure_args+=" --musl-root=/usr"
+		configure_args+=" --set=target.${_host_triplet}.musl-root=/usr"
 		;;
 	esac