Update Rust to 1.46

mingw-w64-rust/0001-add-missing-libs.patch

@@ -2,15 +2,13 @@ diff --git a/src/librustc_llvm/build.rs b/src/librustc_llvm/build.rs
 index caa2740408..52738a47f7 100644
 --- a/src/librustc_llvm/build.rs
 +++ b/src/librustc_llvm/build.rs
-@@ -269,6 +269,9 @@
+@@ -269,6 +269,7 @@
      // LLVM requires symbols from this library, but apparently they're not printed
      // during llvm-config?
      if target.contains("windows-gnu") {
 +        println!("cargo:rustc-link-lib=static-nobundle=ffi");
-+        println!("cargo:rustc-link-lib=static-nobundle=z3");
-+        println!("cargo:rustc-link-lib=stdc++");
-         println!("cargo:rustc-link-lib=static-nobundle=gcc_s");
          println!("cargo:rustc-link-lib=static-nobundle=pthread");
      }
+ }
 -- 
 2.12.0

mingw-w64-rust/0002-fix-install-msys2.patch

@@ -1,13 +1,12 @@
 --- rustc-1.29.2-src/src/bootstrap/install.rs.orig	2018-10-26 14:13:58.455571300 +0300
 +++ rustc-1.29.2-src/src/bootstrap/install.rs	2018-10-26 14:14:35.225835900 +0300
-@@ -74,9 +74,7 @@
-     let bindir_default = PathBuf::from("bin");
-     let libdir_default = PathBuf::from("lib");
-     let mandir_default = datadir_default.join("man");
--    let prefix = builder.config.prefix.as_ref().map_or(prefix_default, |p| {
--        fs::canonicalize(p).unwrap_or_else(|_| panic!("could not canonicalize {}", p.display()))
--    });
-+    let prefix = builder.config.prefix.as_ref().unwrap_or(&prefix_default);
+@@ -74,8 +74,7 @@
+     let prefix = builder.config.prefix.as_ref().map_or(prefix_default, |p| {
+         fs::create_dir_all(p)
+             .unwrap_or_else(|err| panic!("could not create {}: {}", p.display(), err));
+-        fs::canonicalize(p)
+-            .unwrap_or_else(|err| panic!("could not canonicalize {}: {}", p.display(), err))
++        p.to_path_buf()
+     });
      let sysconfdir = builder.config.sysconfdir.as_ref().unwrap_or(&sysconfdir_default);
      let datadir = builder.config.datadir.as_ref().unwrap_or(&datadir_default);
-     let docdir = builder.config.docdir.as_ref().unwrap_or(&docdir_default);