requested changes

- use `link_options.libc_installation == null`
- null-out any objects `comp.crt_files` doesn't know about

Author: mikdusan

src/link/Elf.zig

@@ -3290,11 +3290,6 @@ const CsuObjects = struct {
                     }
                     // Bundled glibc only has Scrt1.o .
                     if (result.crt0 != null and link_options.target.isGnuLibC()) result.crt0 = "Scrt1.o";
-                    // Target linux does not currently support host system toolchain/libc which
-                    // supplies crt begin/end objects so we must disable linking them.
-                    // We leave the above switch data fully populated for future purposes.
-                    result.crtbegin = null;
-                    result.crtend = null;
                 },
                 .dragonfly => switch (mode) {
                     // zig fmt: off
@@ -3334,28 +3329,17 @@ const CsuObjects = struct {
                 },
                 else => {},
             }
-
-            // Bundled { glibc, musl } do not supply begin/end objects.
-            if (comp.wantBuildLibCFromSource()) {
-                result.crtbegin = null;
-                result.crtend = null;
-            }
-
-            // Musl does not supply crti/crtn for all architectures.
-            if (link_options.target.isMusl() and !musl.libc_needs_crti_crtn(link_options.target)) {
-                result.crti = null;
-                result.crtn = null;
-            }
         }
 
         // Convert each object to a full pathname.
-        if (comp.wantBuildGLibCFromSource() or
-            comp.wantBuildMuslFromSource() or
-            comp.wantBuildMinGWFromSource())
-        {
+        if (link_options.libc_installation == null) {
             inline for (std.meta.fields(@TypeOf(result))) |f,i| {
                 if (@field(result, f.name)) |*obj| {
-                    obj.* = comp.crt_files.get(obj.*).?.full_object_path;
+                    if (comp.crt_files.get(obj.*)) |crtf| {
+                        obj.* = crtf.full_object_path;
+                    } else {
+                        @field(result, f.name) = null;
+                    }
                 }
             }
         } else {
@@ -3380,7 +3364,11 @@ const CsuObjects = struct {
                 else => {
                     inline for (std.meta.fields(@TypeOf(result))) |f,i| {
                         if (@field(result, f.name)) |*obj| {
-                            obj.* = try fs.path.join(arena, &[_][]const u8{ crt_dir_path, obj.* });
+                            if (comp.crt_files.get(obj.*)) |crtf| {
+                                obj.* = crtf.full_object_path;
+                            } else {
+                                @field(result, f.name) = null;
+                            }
                         }
                     }
                 }