zig cc: detect -mcpu, -march, -mtune

However these are all treated like zig's -mcpu parameter.

See #4784

src-self-hosted/clang_options_data.zig

@@ -1658,7 +1658,7 @@ sepd1("Zlinker-input"),
 .{
     .name = "library-directory",
     .syntax = .separate,
-    .zig_equivalent = .linker_input_l,
+    .zig_equivalent = .lib_dir,
     .pd1 = false,
     .pd2 = true,
     .psl = false,
@@ -4534,7 +4534,7 @@ joinpd1("target-sdk-version="),
 .{
     .name = "library-directory=",
     .syntax = .joined,
-    .zig_equivalent = .linker_input_l,
+    .zig_equivalent = .lib_dir,
     .pd1 = false,
     .pd2 = true,
     .psl = false,
@@ -5254,8 +5254,22 @@ joinpd1("fixit="),
 joinpd1("gstabs"),
 joinpd1("gxcoff"),
 jspd1("iquote"),
-joinpd1("march="),
-joinpd1("mtune="),
+.{
+    .name = "march=",
+    .syntax = .joined,
+    .zig_equivalent = .mcpu,
+    .pd1 = true,
+    .pd2 = false,
+    .psl = false,
+},
+.{
+    .name = "mtune=",
+    .syntax = .joined,
+    .zig_equivalent = .mcpu,
+    .pd1 = true,
+    .pd2 = false,
+    .psl = false,
+},
 .{
     .name = "rtlib=",
     .syntax = .joined,
@@ -5320,7 +5334,14 @@ joinpd1("gcoff"),
 joinpd1("mabi="),
 joinpd1("mabs="),
 joinpd1("masm="),
-joinpd1("mcpu="),
+.{
+    .name = "mcpu=",
+    .syntax = .joined,
+    .zig_equivalent = .mcpu,
+    .pd1 = true,
+    .pd2 = false,
+    .psl = false,
+},
 joinpd1("mfpu="),
 joinpd1("mhvx="),
 joinpd1("mmcu="),
@@ -5635,7 +5656,7 @@ jspd1("J"),
 .{
     .name = "L",
     .syntax = .joined_or_separate,
-    .zig_equivalent = .linker_input_l,
+    .zig_equivalent = .lib_dir,
     .pd1 = true,
     .pd2 = false,
     .psl = false,

src-self-hosted/stage2.zig

@@ -1288,7 +1288,8 @@ pub const ClangArgIterator = extern struct {
         verbose_cmds,
         for_linker,
         linker_input_z,
-        linker_input_l,
+        lib_dir,
+        mcpu,
     };
 
     const Args = struct {

src/main.cpp

@@ -735,9 +735,12 @@ static int main0(int argc, char **argv) {
                     linker_args.append(buf_create_from_str("-z"));
                     linker_args.append(buf_create_from_str(it.only_arg));
                     break;
-                case Stage2ClangArgLinkerInputL:
+                case Stage2ClangArgLibDir:
                     lib_dirs.append(it.only_arg);
                     break;
+                case Stage2ClangArgMCpu:
+                    mcpu = it.only_arg;
+                    break;
             }
         }
         // Parse linker args

src/stage2.h

@@ -347,7 +347,8 @@ enum Stage2ClangArg {
     Stage2ClangArgVerboseCmds,
     Stage2ClangArgForLinker,
     Stage2ClangArgLinkerInputZ,
-    Stage2ClangArgLinkerInputL,
+    Stage2ClangArgLibDir,
+    Stage2ClangArgMCpu,
 };
 
 // ABI warning

tools/update_clang_options.zig

@@ -176,11 +176,23 @@ const known_options = [_]KnownOpt{
     },
     .{
         .name = "L",
-        .ident = "linker_input_l",
+        .ident = "lib_dir",
     },
     .{
         .name = "library-directory",
-        .ident = "linker_input_l",
+        .ident = "lib_dir",
+    },
+    .{
+        .name = "mcpu",
+        .ident = "mcpu",
+    },
+    .{
+        .name = "march",
+        .ident = "mcpu",
+    },
+    .{
+        .name = "mtune",
+        .ident = "mcpu",
     },
 };