Collapse all uses of target.options.foo into target.foo

with an eye on merging `TargetOptions` into `Target`.

`TargetOptions` as a separate structure is mostly an implementation detail of `Target` construction, all its fields logically belong to `Target` and available from `Target` through `Deref` impls.

compiler/rustc_codegen_llvm/src/debuginfo/gdb.rs

@@ -67,5 +67,5 @@ pub fn needs_gdb_debug_scripts_section(cx: &CodegenCx<'_, '_>) -> bool {
 
     !omit_gdb_pretty_printer_section
         && cx.sess().opts.debuginfo != DebugInfo::None
-        && cx.sess().target.options.emit_debug_gdb_scripts
+        && cx.sess().target.emit_debug_gdb_scripts
 }

compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs

@@ -870,7 +870,7 @@ fn basic_type_metadata(cx: &CodegenCx<'ll, 'tcx>, t: Ty<'tcx>) -> &'ll DIType {
 
     // When targeting MSVC, emit MSVC style type names for compatibility with
     // .natvis visualizers (and perhaps other existing native debuggers?)
-    let msvc_like_names = cx.tcx.sess.target.options.is_like_msvc;
+    let msvc_like_names = cx.tcx.sess.target.is_like_msvc;
 
     let (name, encoding) = match t.kind() {
         ty::Never => ("!", DW_ATE_unsigned),
@@ -981,7 +981,7 @@ pub fn compile_unit_metadata(
     // if multiple object files with the same `DW_AT_name` are linked together.
     // As a workaround we generate unique names for each object file. Those do
     // not correspond to an actual source file but that should be harmless.
-    if tcx.sess.target.options.is_like_osx {
+    if tcx.sess.target.is_like_osx {
         name_in_debuginfo.push("@");
         name_in_debuginfo.push(codegen_unit_name);
     }
@@ -1397,7 +1397,7 @@ fn prepare_union_metadata(
 /// on MSVC we have to use the fallback mode, because LLVM doesn't
 /// lower variant parts to PDB.
 fn use_enum_fallback(cx: &CodegenCx<'_, '_>) -> bool {
-    cx.sess().target.options.is_like_msvc
+    cx.sess().target.is_like_msvc
 }
 
 // FIXME(eddyb) maybe precompute this? Right now it's computed once

compiler/rustc_codegen_llvm/src/debuginfo/mod.rs

@@ -122,12 +122,12 @@ pub fn finalize(cx: &CodegenCx<'_, '_>) {
         // for macOS to understand. For more info see #11352
         // This can be overridden using --llvm-opts -dwarf-version,N.
         // Android has the same issue (#22398)
-        if let Some(version) = cx.sess().target.options.dwarf_version {
+        if let Some(version) = cx.sess().target.dwarf_version {
             llvm::LLVMRustAddModuleFlag(cx.llmod, "Dwarf Version\0".as_ptr().cast(), version)
         }
 
         // Indicate that we want CodeView debug information on MSVC
-        if cx.sess().target.options.is_like_msvc {
+        if cx.sess().target.is_like_msvc {
             llvm::LLVMRustAddModuleFlag(cx.llmod, "CodeView\0".as_ptr().cast(), 1)
         }
 
@@ -251,7 +251,7 @@ impl CodegenCx<'ll, '_> {
         // For MSVC, omit the column number.
         // Otherwise, emit it. This mimics clang behaviour.
         // See discussion in https://github.com/rust-lang/rust/issues/42921
-        if self.sess().target.options.is_like_msvc {
+        if self.sess().target.is_like_msvc {
             DebugLoc { file, line, col: None }
         } else {
             DebugLoc { file, line, col }
@@ -387,7 +387,7 @@ impl DebugInfoMethods<'tcx> for CodegenCx<'ll, 'tcx> {
             });
 
             // Arguments types
-            if cx.sess().target.options.is_like_msvc {
+            if cx.sess().target.is_like_msvc {
                 // FIXME(#42800):
                 // There is a bug in MSDIA that leads to a crash when it encounters
                 // a fixed-size array of `u8` or something zero-sized in a