rustbuild: Distribute libLLVM.so with rustc

A recent change (rust-lang#53245) started to build LLVM with ThinLTO enabled and to
ensure that compile times are kept down it builds LLVM dynamically by default to
ensure that all the various LLVM tools aren't redoing all that optimization
work. This means, however, that all LLVM tools depend on LLVM's dynamic library
by default.

While the LLVM tools and LLDB components were updated to include the shared
library we accidentally forgot about LLD, included with the main rustc
component. LLD also links dynamically to LLVM and ships a non-working binary
right now because of this!

This commit updates our distribution to ship the LLVM dynamic library with the
compiler libraries.  While not technically needed for rustc itself to operate
(right now) it may be needed for LLD, and otherwise it serves as a good basis
for the other LLVM tools components to work with as well.

This should...

Closes rust-lang#53813

src/bootstrap/dist.rs

@@ -501,6 +501,13 @@ impl Step for Rustc {
             t!(fs::create_dir_all(&backends_dst));
             builder.cp_r(&backends_src, &backends_dst);
 
+            // Copy libLLVM.so to the lib dir as well, if needed. While not
+            // technically needed by rustc itself it's needed by lots of other
+            // components like the llvm tools and LLD. LLD is included below and
+            // tools/LLDB come later, so let's just throw it in the rustc
+            // component for now.
+            maybe_install_llvm_dylib(builder, host, image);
+
             // Copy over lld if it's there
             if builder.config.lld_enabled {
                 let exe = exe("rust-lld", &compiler.host);
@@ -1967,8 +1974,6 @@ impl Step for LlvmTools {
             builder.install(&exe, &dst_bindir, 0o755);
         }
 
-        maybe_install_llvm_dylib(builder, target, &image);
-
         // Prepare the overlay
         let overlay = tmp.join("llvm-tools-overlay");
         drop(fs::remove_dir_all(&overlay));
@@ -2087,9 +2092,6 @@ impl Step for Lldb {
             }
         }
 
-        // Copy libLLVM.so to the lib dir as well, if needed.
-        maybe_install_llvm_dylib(builder, target, &image);
-
         // Prepare the overlay
         let overlay = tmp.join("lldb-overlay");
         drop(fs::remove_dir_all(&overlay));